Match ends, Manchester United 2, Arsenal 2.
Manchester United showed "big heart and soul" to twice come from behind to earn a draw against Arsenal, said manager Jose Mourinho.
Mourinho dropped high-profile duo Paul Pogba and Romelu Lukaku after recent disappointing performances which have brought only three points from the past 12 available - and, while quality was lacking, no-one could doubt his side's endeavour and character.
Goalkeeper David de Gea made an uncharacteristic error as he failed to deal with Shkodran Mustafi's tame 26th-minute header, which Ander Herrera could not clear before it crossed the line.
United were swiftly level through Anthony Martial after Arsenal keeper Bernd Leno could only half-clear a free-kick to set up an exciting second half.
Substitute Alexandre Lacazette scrambled Arsenal back in front after 68 minutes but United were on terms once more within seconds as Jesse Lingard pounced on Sead Kolasinac's attempted backpass.
De Gea redeemed himself with a succession of fine saves as both sides had to content themselves with a point, with United now eighth in the Premier League and Arsenal, who extended their unbeaten run this season to 20 games, dropping to fifth.
"As always we made mistakes and we paid for the mistakes," said Mourinho.
"Today was more the same, but with great spirit and people ready to have a go and fight hard. It was a credit to the team."
Mourinho's men show grit, but little quality
Mourinho demonstrated he would not shy away from taking the big decisions as Pogba and Lukaku were consigned to the bench - he will have known the spotlight would have shone on him in unforgiving fashion had United lost.
In the end, it was a performance that was satisfying in parts but merely emphasised just how far United are behind the pacesetters.
United may not, as Mourinho complained, have any "mad dogs" in their side, but there was at least some bite about this display after recent tame efforts against Crystal Palace here, and at Southampton.
That was appreciated by United's fans as a starting base, but there was little to suggest this was a team whose season was about to burst belatedly into life.
United's attack was more fluid and mobile with Martial and Marcus Rashford selected ahead of Lukaku but there was still a lack of creativity, and while the effort was there, the real spark was missing.
Mourinho will be pleased at the manner in which United responded to Arsenal's goals, helped by the Gunners' sloppiness, and these were players who were undoubtedly putting in the work for their manager.
This is, however, a pale shadow of a side that will chase the big prizes.
Mixed feelings for Arsenal boss Emery
Arsenal will, ultimately, probably be happy with a point at a ground where their recent record is miserable, and against opponents who were attempting to put down a marker after recent criticism.
Gunners boss Unai Emery, however, will feel disappointment that they did not leave with all three points after twice holding the advantage only to concede it quickly.
Emery's frustration was obvious when Lingard scored United's second equaliser moments after Lacazette had restored their lead, as he knew had they held their advantage a little longer there is every chance United could have become frustrated.
The manner in which it was conceded will have also infuriated the animated Emery, United striking back right from the kick-off with the aid of Kolasinac's error.
On the plus side, Arsenal coped well with United's predictable late aerial siege and this is a point that consolidated their good start to the season and extends that fine unbeaten sequence.
Emery may have wanted the win as Arsenal failed to reproduce the electrifying form that beat Spurs in the north London derby but there was still plenty to satisfy him.
Man of the match - Eric Bailly (Manchester United)
Manchester United manager Jose Mourinho: "We scored four goals and drew 2-2! As always we made mistakes and we paid for the mistakes.
"Today was more the same, but with great spirit and people ready to have a go and fight hard, it was a credit to the team.
"They went to the limit and were really tired. Some of them had not played all season, Chris Smalling playing in very difficult condition, but Arsenal were only dangerous when we lost the ball in bad areas.
"Even from our bench you could feel the little panic when the ball comes to our defensive third.
"The spirit was Manchester United level but we miss certain qualities.
"I have to disagree with people who try to compare this to teams of Roy Keane, Ruud van Nistelrooy, Nemanja Vidic. Give us a break and time. I am happy with the soul and heart, but we are not consistent and uniform."
Arsenal manager Unai Emery: "I think we controlled the game, the second half better than the first. We could have won this match in certain moments, but they equalised very quickly after both our goals.
"We need to improve defensively, but we need to have balance and not lose our attacking chances.
"We perhaps lost a bit of control there but we created lots of chances after 2-2 and I am very proud of our performance. We wanted to win but we can feel this point is good."
United continue leaking goals - the stats
- Manchester United manager Jose Mourinho has only lost one of his 16 games against Arsenal in the Premier League (winning seven and drawing eight) and remains unbeaten in home games in the competition against them.
- Arsenal are now unbeaten in their last 20 games in all competitions, their longest such run since November 2007 (28 games).
- Manchester United have conceded more goals at Old Trafford in the Premier League this season (10 goals in seven games) than they did in the whole of 2017-18 (nine in 18 games).
- Arsenal are still yet to lead a Premier League game at half time this season, although they haven't gone on to suffer a defeat in the competition since August (2-3 v Chelsea).
- Manchester United winger Anthony Martial has scored seven goals in his last seven starts in the Premier League, with three of those coming at Old Trafford.
- Jesse Lingard's second half equaliser for Manchester United came 74 seconds after Arsenal had retaken a 2-1 lead, and just 13 seconds after restarting the game from kick-off.
- Manchester United made a total of seven changes to their starting XI against Arsenal - indeed, they have made more than any other team in the Premier League this season (46).
Manchester United play Fulham at home on Saturday at 15:00 GMT with Arsenal entertaining Huddersfield at the same time.
- 1De Gea
- 16RojoBooked at 38minsSubstituted forFellainiat 72'minutes
- 31MaticBooked at 42mins
- 14LingardBooked at 40minsSubstituted forPogbaat 75'minutes
- 11MartialSubstituted forLukakuat 63'minutes
- 25A Valencia
- 20MustafiBooked at 37mins
- 16HoldingSubstituted forLichtsteinerat 36'minutes
- 2BellerínBooked at 41mins
- 11TorreiraBooked at 86mins
- 8RamseySubstituted forMkhitaryanat 45'minutes
- 17IwobiSubstituted forLacazetteat 65'minutes
- Andre Marriner
- Shots on Target
Second Half ends, Manchester United 2, Arsenal 2.
Delay over. They are ready to continue.
Delay in match Stephan Lichtsteiner (Arsenal) because of an injury.
Offside, Arsenal. Sead Kolasinac tries a through ball, but Alexandre Lacazette is caught offside.
Offside, Arsenal. Lucas Torreira tries a through ball, but Henrikh Mkhitaryan is caught offside.
Attempt saved. Lucas Torreira (Arsenal) right footed shot from the centre of the box is saved in the top right corner. Assisted by Henrikh Mkhitaryan.
Offside, Manchester United. David De Gea tries a through ball, but Marouane Fellaini is caught offside.
Dangerous play by Alexandre Lacazette (Arsenal).
David De Gea (Manchester United) wins a free kick in the defensive half.
Matteo Guendouzi (Arsenal) wins a free kick in the attacking half.
Foul by Marouane Fellaini (Manchester United).
Lucas Torreira (Arsenal) is shown the yellow card for a bad foul.
Attempt saved. Marcus Rashford (Manchester United) right footed shot from outside the box is saved in the centre of the goal. Assisted by Ander Herrera.
Lucas Torreira (Arsenal) wins a free kick in the defensive half.
Foul by Marouane Fellaini (Manchester United).
Attempt blocked. Marouane Fellaini (Manchester United) right footed shot from the left side of the box is blocked. Assisted by Diogo Dalot with a cross.
Substitution, Manchester United. Paul Pogba replaces Jesse Lingard.
Corner, Arsenal. Conceded by David De Gea.
Attempt saved. Pierre-Emerick Aubameyang (Arsenal) right footed shot from outside the box is saved in the bottom right corner. Assisted by Sead Kolasinac.