Thanks for joining us on a night that many of us thought we'd never see.
Yaya Sanogo has scored a goal.
Thanks for joining us on a night that many of us thought we'd never see.
Yaya Sanogo has scored a goal.
Arsenal's injured playmaker Mesut Ozil on Twitter: "Well-deserved win, great rematch, qualified for the round of sixteen - what a perfect evening. Superb performance, Gunners!"
Arsenal's win dumped Anderlecht out the tournament, despite the Belgians' 2-0 win over 10-man Galatasaray.
However Chancel Mbemba's brace has ensured the Brussels side will be in the Europa League.
Yaya Sanogo's Twitter handle is 'Yayasanogoal22'. He might have to change that now. Yayasanonegoal22 maybe?
Arsenal manager Arsene Wenger on Sky Sports: "Overall it was a committed game.
"Maybe we were defensively better tonight. We are a team that likes to go forward - sometimes we feel dominate the game and we maybe forget to take precautions to defend. We did that better tonight.
"Alexis Sanchez has given unbelievable fighting spirit. A mixture of talent and desire.
"I like what Yaya Sanogo did tonight. We went long on him. What he did on his first goal is class. Unfortunately, he got injured. Mikel Arteta doesn't look good - it's a calf. I think he will be out for a while.
"The injuries are difficult to take on the chin. We go into many games and we need as many available."
I was impressed by Lukasz Piszczek, Borussia Dortmund's right-back tonight, definitely one out of the Dani Alves school of defending.
Arsenal boss Arsene Wenger has just been on TV saying that midfielder Mikel Arteta could be out for a while with a calf injury picked up tonight.
He was replaced after 67 minutes today.
Full quotes to come.
Thanks to Opta's touchmap, we can see that Santiago Cazorla put in a real box-to-box performance. Impressive stuff from the Spaniard.
Mark Lawrenson, former Liverpool defender, on 5 live
"An awful lot of teams would love to be in Arsenal's position. Apart from Chelsea and Southampton, who can you say has played really well?
"I'm totally convinced Arsenal will qualify for the Champions League via the Premier League again. It's just whether the people at the top think it's time for a change.
"You'd just like the manager to put his hand up and admit he's been a bit stubborn and try to build the team from the back."
Arsenal defender Per Mertesacker on Sky Sports: "It was a solid performance, especially defensively.
"We didn't give them too much. We were solid at the back. We have had a few disappointing results recently. That was a mental test and we are strong enough. We can continue now.
"It's good to score an early goal but over the 90 minutes we were solid and that's the key.
"We had to [sit down and discuss recent poor defensive performances]. After Anderlecht and Manchester United, we dropped mentally a bit. We were even stronger today. We learned form disappointments in the last weeks.
"In the Premier League we have to prove something there. Some vital weeks are coming up."
The stats tell us there wasn't much in the game - Borussia Dortmund had more possession and shots on target, while Arsenal had one shot more than the Germans.
Real Madrid have sealed a 1-0 win in Basel courtesy of Cristiano Ronaldo's goal to mean that Liverpool only need to beat the Swiss side at Anfield to go through from Group B.
Carlos Tevez wrapped up victory for Juventus in Malmo with a comfortable finish after breaching the offside trap. The Italians are in pole position to qualify from Group A with Atletico Madrid who completed a comfortable passage into the knockout stages with a 4-0 win over Olympiakos.
Meanwhile Group C promises to be a fascinating final day with Monaco's surprise 1-0 win in Bayer Leverkusen meaning both those teams and Zenit St Petersburg can go through.
Anderlecht's 2-0 victory over Galatasaray has become academic in Group D with both Arsenal and Borussia Dortmund qualifying.
So Arsenal are through. A victory in their final game at Galatasaray would see them top the group but only if Borussia Dortmund are beaten by Anderlecht, who have nothing to play for.
This is the 15th consecutive season that Arsenal have qualified from the Champions League group stage. They're consistent if nothing else. Very consistent.
Arsenal have been deserved winners tonight and they're into the knockout stages again.
Borussia Dortmund were poor, but the Gunners played well.
Adrian Ramos almost pulls one back but it's straight at Emiliano Martinez. Two minutes left.
Santi Cazorla is grimacing after being caught by Adrian Ramos. Not what Arsenal fans need to see.
We're approaching injury-time, Joel Campbell comes on for the impressive Alex Oxlade-Chamberlain.
Four added minutes.
Ludogorets have equalised against Liverpool in Bulgaria, but I'm reliably informed that changes nothing to the qualification permutations.
Jack in London: Calling Arsenal fans fickle is quite a generalised statement. I personally still want Wenger to step down at the end of the season.
Optimistic Gooner: All fine and dandy but as always into the last 16 and it will be there we meet real class and a swift return to reality and the chase for fourth!
BBC Radio 5 live
What have you made of this evening's action?
With Yaya Sanogo scoring his first goal for Arsenal, do you expect to see him regularly? Or at the very least, has he justified his selection?
Have your say on the 5 live Football Social from 22:00 GMT on the BBC Radio 5 live website. Text 85058 or Call 0500909693.
The phones lines are open now - and Mark Pougatch wants to hear from you.
I was just about to ask the same question, Earl.
Aaron Adegbesan: As an Arsenal fan I think Wenger should not be sacked unless he fails to win another trophy by the end of next season.
Lindsay: I'm enjoying this Arsenal performance but we still need to perform in the premier league or we won't be back here next season.
The Earl of Jeffs: Would Arsenal fans take Jurgen Klopp on this showing?
Phil: The Wenger-cokey is off again - we want Wenger in, Wenger out, in out, in out shake him all about. Fickle fans.
Steve Watson: Arsenal need to win the group not to draw one of the big guns (Bayern, Barca, etc).
Ilkay Gundogan has an effort from 20 yards but it's easily saved by Arsenal keeper Emiliano Martinez, who could be pocketing an unexpected clean sheet bonus tonight.
I suspect Yaya Sanogo would have settled for today's events this morning. Well, presuming his injury isn't too serious.
Really hard to see Borussia Dortmund mounting a comeback here.
A potential minor shock on the cards in Group C as Monaco take the lead in Bayer Leverkusen with their first shot on goal all evening. Lucas Ocampos had only been on the field two minutes when he slotted home a Nabil Dirar cross from the right.
Yaya Sanogo is limping off, seems to be holding his hamstring. He's milking the applause as he comes off slowly.
And he is replaced by Lukas Podolski.
Kevin Grosskreutz plays a cross across goal but nobody can get on the end of it. He is immediately replaced by Milos Jojic - Borussia Dortmund's final change.
Luke Gwalchmai: This is exactly what Arsenal didn't do against Anderlecht; actually defend!
Wil: Arsenal fans will want Wenger out as soon as they lose their next game, their fans are beyond pathetic.
Bradders: When Wenger wins, he's the best. When we lose fans call for his head. Arsenal fans are fickle. Coming from an Arsenal fan.
Alex Oxlade-Chamberlain goes close for a second time. Alexis Sanchez plays a cross-field pass to the England midfielder, who takes a touch and fires in a powerful effort which flies just over.
A reminder that a third Arsenal goal would boost their chances of topping the group on the final day.
The Gunners look like they're going to see this one out, defending solidly. But I feel like a thousand text commentators have probably said that before me and been proved wrong.
BBC Radio 5 live
Imagine what Alexis Sanchez will be like once he's settled. Simply brilliant curled effort into the corner. His 13th for the club.
Yaya Sanogo is back in his own half helping out, but concedes a free-kick for a mistimed tackle. Borussia Dortmund take a quick set-piece and Neven Subotic fires over a very ambitious 40-yard effort as the ball is rolled to him.
Mario Mandzukic has scored a hat-trick for Atletico Madrid to make it 4-0 against Olympiakos in Group A. The Croatia striker netted his second on 62 minutes heading in from Arda Turan's cross and then nodded home a Gabi free-kick three minutes later.
Abdul Said: Sanchez is not for sale! Caution, Man City.
Nappier O George: What a stunner from the Chilean machine. What a great addition to this Arsenal team. Complete player he is. Good buy Wenger.
Kurt Booth: Credit to Sanogo for eventually delivering the goods, and to Sanchez for doing it on the regular, including today.
New captain Per Mertesacker is down injured after a clash of heads with substitute Adrian Ramos.
The German picks himself up, as does Ramos eventually.
Arsenal make a change as Mikel Arteta comes off for Mathieu Flamini.
Arteta hands the captain's armband over to Per Mertesacker.
Twenty-three minutes to see this out now.
Antoine V: People saying sack Wenger and he'd be gone if not for Sanchez... Remind me, who brought the amazing Sanchez to Arsenal?
Benhard Naweseb: The reason why Arsenal will win tonight is because Wenger has been out of his seat a few times already. Fire in the belly.
Luke: South American class has taken over the PL in the striking department. Sanchez, Aguero and Costa are miles ahead of anyone
So if both games end now, Arsenal can still finish top of Group D if both results go their way in two weeks' time. If the Gunners beat Galatasaray in Turkey, and Borussia Dortmund lose at home to Anderlecht, Arsenal will win the group.
If Arsenal win this game 3-0, then even a Dortmund draw on the final day would see the Gunners through if they win in Istanbul.
And Jurgen Klopp makes a double change up front, almost immediately. Former Manchester United player Shinji Kagawa and Adrian Ramos come on for Ciro Immobile and Pierre-Emerick Aubameyang.
It just hasn't worked today for the Bundesliga strugglers.
Is that the Gunners home and dry? Never count on it against a Jurgen Klopp side, even one that doesn't need to win.
Having said that, as things stand this lets the Gunners back in the race for top spot and potentially an easier last-16 tie.
MuLoRm: Sanchez is PURE QUALITY!
Arsenal legend Ian Wright was talking to BBC Radio 5 live this week about Sanchez and said: "They are mid-table without him."
Great goal by a great player. Santi Cazorla plays the ball forward to Alexis Sanchez, Arsenal's standout player this season, and he cuts inside before curling a fantastic effort from 20 yards past Roman Weidenfeller into the corner of the net.
Jigga T: Yaya Sanogo people were hating on him. Good for you. Score a hat-rick to shut them up.
Kurt Booth: Sanogo scoring, Arsenal leading in Europe...all we need now is fire, brimstone and four horsemen, and all the pieces fit!
Goonerama: Ramsey still bombing forward + Arteta on a yellow = worrying.
Juventus have put themselves in pole position to join Atletico Madrid from Group A in the knockout stages. Fernando Llorente has burst through the Malmo defence from Claudio Marchisio's pass four minutes into the second half to break the deadlock in Sweden. Malmo will be eliminated as things stand.
Almost a fantastic goal by Alex Oxlade-Chamberlain, the Arsenal midfielder controls the ball well 20 yards from goal and he half-volleys a near-perfect strike on his laces which hits the crossbar. Keeper Roman Weidenfeller was nowhere near it.
Borussia Dortmund are trying to get the ball forward to pacy striker Pierre-Emerick Aubameyang at every opportunity now, but he's just snuffed out by a Gunners defender on a couple of opportunities.
The home side's defence will have to remain alert.
Phil: We really need a proven premier league frontman. How about a certain Theo Walcott. Play him through the middle and see the goals come.
On one of the Gunners' first runs forward in the second half, Alexis Sanchez takes the ball on 40 yards from goal, charges past a couple of Borussia Dortmund defenders and then has a powerful shot saved down low by Roman Weidenfeller.
Borussia Dortmund have had most of the ball in the second half, practically all of it, it feels.
A couple of crosses into the box are cleared and then Ctrl+v, sorry Henrikh Mkhitaryan, has a shot from just outside the box that is straight at Emiliano Martinez.
Between Bayern Munich taking one of their world-class players every summer, and Marco Reus being injured, Borussia Dortmund haven't looked the side we have all raved about in previous seasons.
Borussia Dortmund get the second half going. They need a draw tonight to clinch top spot in the group.
Players are coming out for the second half. I can't imagine either side will have made a change.
'One minute to kick-off' says an informative sign at the Emirates.
Ancelotti says when Cristiano Ronaldo starts it's the equivalent of a one goal start. Correct again, Carlo.
Real Madrid lead 1-0 in Basel. Cristiano Ronaldo scores his 71st Champions League goal - that would have been the joint-record until yesterday's Lionel Messi hat-trick.
Ronaldo has now scored in 11 consecutive away games in the competition plus last season's final.
As things stand Arsenal are through to the last 16, and still have a chance of topping the group. They visit Galatasaray in two weeks' time in the final group game.
Elsewhere in Group D, Anderlecht have just taken the lead through Chancel Mbemba Mangulu a minute before the break against Galatasaray.
Atletico Madrid are now cruising into the knockout stages after Mario Mandzukic gives them a 2-0 lead over Olympiakos in Group A. Alberto Botía cannot clear a Cristian Ansaldi cross and Mandzukic capitalises. It remains goalless in the other Group A game between Malmo and Juventus, and the Group C encounter between Bayer Leverkusen and Monaco.
It's half-time in Sofia, as Liverpool have come from a goal behind to lead Ludogorets Razgrad. Jordan Henderson was their second scorer.
Just 73 seconds is what it took for Yaya Sanogo to repay Arsene Wenger's faith with his first goal for the Gunners.
Arsenal going into the last 16 as things stand.
Sven Bender has a pop from the edge of the box but it spins off his foot and loops into the hands of Emiliano Martinez. You feel as if Borussia Dortmund will score at some stage in this game. They need a point to win the group.
Jack Elphick-Calle: Really good solid performance from Arsenal so far. Arteta, Gibbs, Chamberlain and Cazorla stand-out performers thus far for me.
John de Vliering: Gibbs playing really well tonight. Hope he stays injury-free to get a good run of games.
Alan Walsh: Hmmm so Arsenal are currently 1-0 up, that means the game will end 2-1 to Dortmund.
This is the closest Borussia Dortmund have come and it's a good save by Emiliano Martinez to deny them. Lukasz Piszczek heads down a ball forward to Henrikh Mkhitaryan, who is denied by Martinez's save down low.
Arsenal would probably like to hear the half-time whistle now.
Small bit of worry in the Borussia Dortmund defence for a moment as a long ball is played over the top for Yaya Sanogo to run onto. Keeper Roman Weidenfeller rushes out of his box to deal with it though.
Lukasz Piszczek is then booked for pulling back Kieran Gibbs. The Dortmund right-back has to be on his best behaviour now for the whole second half.
Borussia Dortmund break with speed king Pierre-Emerick Aubameyang but instead of taking it into the box he tries to cross it to Henrikh Mkhitaryan and Per Mertesacker comes to the rescue. A bit of a let-off for the Gunners.
Arsenal boss Arsene Wenger will be pleased with what he's seen so far. The Gunners keeping possession well at the moment.
Borussia Dortmund right-back Lukasz Piszczek is going forward at every opportunity, he's been one of his side's most attacking threats. His latest cross is straight at Emiliano Martinez however.
Let's call this a minor penalty shout as Lukasz Piszczek charges into the box, Kieran Gibbs pokes the ball away from him and then brings the Borussia Dortmund right-back down with the follow-through from his tackle.
He didn't really call for it, but some of the visiting fans did.
Borussia Dortmund right-back Lukasz Piszczek goes down after an accidental arm in the face from Alex Oxlade-Chamberlain. He is OK to play on though, a relief for Dortmund as they can't afford to lose more players to injury.
Play is fairly even at the moment, both sides trying to go forward at every chance.
It's hard to know what Henrikh Mkhitaryan was trying to do there, the Borussia Dortmund attacking midfielder controls a lofted cross about 16 yards out and tries to hit it with his laces and it goes over. Seemed a more standard club from his bag might have worked there.
Borussia Dortmund have their first proper sniff at goal as Lukasz Piszczek who fizzes a low ball across goal but Ciro Immobile just can't stretch far enough to turn it in. There was an empty net for him if he could as keeper Emiliano Martinez had been taken out of the equation by the cross.
Ben from Lymington: You can tell Sanago plays for Arsenal. Do the hard stuff with some lovely skill and finish, then through on goal and wastes a great chance. Frustrating!
Ben in Lymington: Wenger in? Wenger out? What's it going to be after this game?
Arsenal are looking threatening going forward today, with Alexis Sanchez becoming more and more central to the game. Of course we all know that the Gunners' problems are usually at the other end.
On Twitter: I hear that Sanogo has scored. 'Hear' rather than 'see' as we've managed to lock ourselves out of our own home. Such joy!
I'm sure Gary is following the game on the BBC Sport app.
Alexis Sanchez is a fantastic player, three Borussia Dortmund defenders surround him and it takes a foul from Neven Subotic to stop him. The centre-back is the first player in the book today.
In Group A, Atletico Madrid have taken the lead and it has come from another defensive error. Olympiakos goalkeeper Roberto inexplicably plays the ball straight to Juanfran who crosses to Raul Garcia for a tap-in.
Corner to Arsenal, Alexis Sanchez - who has been quiet so far - wins it and Santi Cazorla whips it in but it's cleared by Dortmund, who counter with Henrikh Mkhitaryan.
Pierre-Emerick Aubameyang, one of the fastest players around, thinks he might be in for a second but Kieran Gibbs does well to tackle him.
Yaya Sanogo has a chance for a second. He is played in on goal, he has the chance to fire home with his right foot from 18 yards but he tries to cut back onto old lefty, where he runs into a Borussia Dortmund player.
Still the chance is not gone as the Dortmund player gives the ball back to Sanogo, but his shot is off target. Wasteful.
Harry Gray: Has anyone got a hat for me to eat? Sanogoal!!
Cheggers Peterborough: Well then.... That shut me up.
...But Liverpool are now level, Rickie Lambert heading home via the post.
There's been an early goal involving the other Premier League side in Champions League action today.
Liverpool trail Ludogorets Razgrad 1-0, with keeper Simon Mignolet at fault.
Borussia Dortmund push for a leveller straight away but a shot comes off Pierre-Emerick Aubameyang, who was in an offside position.
They have not dropped a point in the Champions League yet this season.
Atletico Madrid will look to secure their place in the knockout stages of the Champions League. The Spanish side need a victory over Olympiakos to guarantee their progress with a game to spare. All four sides can still qualify from Group A with Malmo, currently on three points, hosting Juventus who have six.
Victory for Bayer Leverkusen over Monaco will guarantee their progress from Group C. Russian side Zenit St Petersburg have given their own qualification hopes a major chance with a 1-0 win against Benfica earlier in the day meaning the Portuguese side are unlikely to qualify. Danny scored the goal 11 minutes from time.
You cynics! Yaya Sanogo shows why boss Arsene Wenger starts with him as he receives a throw-in with his back to goal, does a bit of keepy-ups, backheels the ball to Santi Cazorla, who plays the ball back to the Frenchman to fire home.
Arsenal get us under way at the Emirates. A draw in either game in this group takes the Gunners through.
Tom Colman: It must crush Hector Bellerin's confidence seeing a CB starting over him in his position. I know he is young but he needs a chance.
Aj: Only player that doesn't deserve arsenal shirt is Yaya Sanogo and he is getting place in starting XI in such a crunch game.
Nick meel: Sanogo starting...... what do u see in him Wenger? Hope he proves your faith in him today.
Both sets of players - with mascots in tow - come out of the tunnels.
It's Champions League anthem time - my wait for some legend to start singing along to it goes on sadly.
Moments to go.
Just a reminder of tonight's line-ups. Arsenal have 17-year-old Ryan Huddart as their back-up keeper on the bench.
Arsenal: Martinez, Chambers, Mertesacker, Monreal, Gibbs, Arteta, Oxlade-Chamberlain, Ramsey, Cazorla, Sanchez, Sanogo. Subs: Huddart, Koscielny, Rosicky, Podolski, Flamini, Campbell, Bellerin.
Borussia Dortmund: Weidenfeller, Piszczek, Subotic, Ginter, Schmelzer, Mkhitaryan, Bender, Gundogan, Grosskreutz, Immobile, Aubameyang. Subs: Langerak, Hornschuh, Kehl, Kagawa, Jojic, Ramos, Durm.
Referee: Viktor Kassai (Hungary)
Mick Champness: Pack your bags Lukas Podolski and join a club where the manager appreciates what you can offer. Utter joke, Wenger!
Roger Lidher: Time for Wenger to go now. He's out of touch with reality. Talks about solidarity but has been letting the fans down for years as he won't accept his mistakes and rectify them.
These clubs played in the Uefa Youth League earlier today. Arsenal's Under-19s beat Dortmund 1-0 at Meadow Park.
Daniel Crowley missed a penalty but Stephy Mavididi tapped in Alex Iwobi's cross for the only goal.
In September's opening group match, Arsenal lost 2-0 to Borussia Dortmund, with Ciro Immobile and Pierre-Emerick Aubameyang netting.
Ex-Gunners striker John Hartson told BBC Radio 5 live: "They could have conceded five or six. Without overreacting, it was a really woeful defensive performance from Arsenal."
Jamie Plummer: What's the point of having Joel Campbell in the squad if he's not going to give him a go?
BlueJaysGooner: Not surprised Dortmund trained in Regent's Park. Arsenal have been playing like a Sunday league team of late.
Anisa: Wenger has lost the plot. Sa-No-Goal instead of Podolski? Monreal instead of Koscielnly? Does he even want to qualify?
Arsenal midfielder Aaron Ramsey has backed boss Arsene Wenger after criticism from the club's second-largest shareholder Alisher Usmanov.
"With what he's done for this club and for us as a group of players, every time we go in we want to work for him and get results for him," Ramsey told Sky Sports News.
"Everybody's in it together, and we know all about our qualities. Last season we had a great year, this season we wanted to build on that and hopefully we still can."
Kerry Peter Parvin: The Arsenal line up is a joke! Is Wenger doing this on purpose? Ruining the club before he goes!
Ezeakum Ugochukwu: Again Wenger setting arsenal up to lose, so predictable its pathetic. Can't understand how Bellerin can't get a game.
Mathew Brown: This Arsenal line-up tonight has no chance against Hummels and Reus and co. Oh dear, oh dear.
Mark Lawrenson on 5 live
"The whole thing about Arsenal for me is, Arsene Wenger inherited a strong defensive team and since the Invincibles, he's started to build his teams from front to back.
"The best teams ever are built from back to front. You need that platform so you can take on any team and gamble in attack.
"They don't have any leaders. I would regard myself as a fan of Arsene Wenger but he must build his team from the back next time - if he gets time to do it."
Borussia Dortmund got in a cheeky training session this morning, but it wasn't at the Emirates. Or Arsenal's training ground.
In fact it was on a pitch more commonly used to host matches in the Camden and Regent's Park Sunday league.
New for this season we have a Champions League tracker page with as-it-stands groups, latest scores, fixtures and results. Have a look.
BBC Radio 5 live
BBC Radio 5 live: Wenger believes. Do you believe #AFC fans? Listen live on this page for updates on #AFCvBOR
Arsenal boss Arsene Wenger has called for unity at the club despite their shaky start to the season.
Major shareholder Alisher Usmanov suggested Wenger has been making mistakes.
But the Frenchman said: "Everybody has the right to have an opinion, having said that, we have values at this club.
"During the 18 years I have been here, I have shown that I can take criticism. I don't take it personally at all.
"It is an opinion that I respect, but when you are from this club, you are from this club. You are in or out, you cannot be both."
Both managers have predictably been asked about their opponents' problems in the league.
Arsene Wenger says: "They had many injuries at the start of the season. Because they are a big club, the questions come very quickly - 'why do you lose?' - and then the confidence drops a little bit.
"I don't worry too much for them in the league. I don't think they will stay where they are at the moment."
Jurgen Klopp thinks: "I don't know whether the people here expect Arsenal to walk through the league. But the Premier League is too strong to walk through it. And if Wenger faces some pressure, then that's normal."
Sam Ward: I would 100% take Klopp, right now, but I would hate to see Wenger go, but I think it needs to happen, tide is turning amongst us Gunners fans.
If you want to follow Liverpool's match against Ludogorets Razgrad in Sofia tonight, where the Reds could go out, follow Gary Rose's live text updates - and 5 live commentary - of that game here.
What does Yaya Sanogo do in training that gets him in the team ahead of Joel Campbell, who scored goals in the Champions League last season for Olympiakos and also netted in the World Cup for Costa Rica?
Don't forget you can stay across all of tonight's action with Midweek Final Score. Just click the play button at the top of the page.
Lots of Champions League action tonight and plenty to keep the old permutations calculator busy. One has already finished, with Zenit St Petersburg beating Group C rivals Benfica. Portugal midfielder Danny's strike moves the Russians into second place, ahead of Monaco's trip to Bayer Leverkusen.
Ryan Lovell: Arsenal will win the match 3-1 - you heard it here first.
James Lockey: Wenger will step down this season and Klopp will take over. Looking more and more likely.