Match ends, Chelsea 1, Barcelona 1.
Lionel Messi's first goal in nine Champions League games against Chelsea gave Barcelona a potentially vital away goal as they rode their luck to earn a draw in the first leg of their last-16 tie at Stamford Bridge.
The Blues had subdued Messi, and Willian had struck the woodwork twice in the first half before a fine low finish from the edge of the area made it third time lucky for the Brazilian and gave Antonio Conte's side a deserved lead after 62 minutes.
Barcelona had barely threatened but a misplaced pass from Andreas Christensen gave Andres Iniesta the opportunity to allow Messi to end his 730-minute drought against Chelsea with a crisp left-foot drive 15 minutes from time.
It was cruel on the hosts after an outstanding display - but gives Barca the advantage of an away goal for the return leg at the Nou Camp on Wednesday, 14 March.
The result does mean none of the English teams have lost in their last-16 first-leg ties so far.
In Tuesday's other Champions League match, German champions Bayern Munich thrashed Besiktas 5-0 after the Turkish side had Domagoj Vida sent off in the 16th minute.
- Reaction: Chelsea can do 'something incredible'
- Relive Chelsea's match with Barcelona as it happened
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Conte's master plan almost pays off
Chelsea and Conte knew they needed a performance of fierce tactical discipline and near perfection to establish a platform.
And they came so close to achieving it until that moment in the 75th minute that might yet prove decisive in this tie.
Conte's decision to play with Eden Hazard as a "false nine" and have plenty of bodies around Barcelona's brilliant creators worked superbly as Willian gave them the lead they fully deserved just after the hour.
Only ill luck and both posts had prevented the hosts from building an advantage earlier. And Chelsea's organisation and willingness to contest every situation frustrated Barcelona, even the world-class pairing of Messi and Luis Suarez.
In Willian, Chelsea had the game's outstanding performer. He rattled both posts and ran Barcelona ragged with his pace and strong running.
The Blues fans were just beginning to contemplate taking a precious lead to the Nou Camp when Christensen, outstanding this season, misplaced a pass across his own area with catastrophic consequences.
Iniesta picked the perfect pass for Messi to complete the formalities with a sweeping left-foot finish.
Chelsea's concentration may have been disturbed by penalty appeals a second earlier when Suarez tangled with Antonio Rudiger - but it was the sort of error that rarely goes unpunished by opposition of such quality.
The home side and the work of their manager - who said he had sleepless nights working out a plan to combat Barcelona - deserve so much credit on a night when they put their recent struggles behind them and looked much more like last season's Premier League champions.
Messi breaks Chelsea drought
Chelsea had managed to establish an unlikely stranglehold on the genius of Messi - until he provided the emphatic finish that gave his side a potentially crucial away goal.
The 30-year-old Argentina forward had not scored against Chelsea in eight previous Champions League appearances - and for large portions of a high-quality game it looked as though he would be frustrated once more.
Chelsea's prodigious work-rate ensured he either ran into a mass of bodies or out of room on countless occasions, although one darting run at lightning pace in the first half brought audible gasps from the crowd.
Messi, along with Suarez, were kept at arm's length for much of this game, but it only takes one slip against this Barcelona team, even when they are out of sorts.
Iniesta was the creator on the left edge of the area, and Messi did not even break stride before firing low past Thibaut Courtois, causing even understated Barca coach Ernesto Valverde to show a flash of emotion.
Can Chelsea still qualify?
Chelsea's players were a picture of obvious and understandable disappointment as they trooped off at the final whistle - but it was with the applause of the home support ringing in their ears.
This was in recognition of an outstanding team performance that did not get the reward it deserved and must serve as encouragement for the second leg in Barcelona.
Chelsea, underpinned by Conte's tactical nous, proved they could both threaten and subdue their opponents - and they must do it again.
Barcelona, however, must be favourites because the momentum is now with them and the balance and emphasis of the tie shifted in the time it took Messi to score that crucial goal.
Chelsea, however, demonstrated they have no reason to fear the Spanish side, and past history has also shown they can defy the odds, as they did to beat this same opposition in the 2012 Champions League semi-final on the way to lifting the trophy in Munich.
Man of the match - Willian (Chelsea)
'Close to the perfect game' - what they said
Chelsea manager Antonio Conte said: "I think we were close to playing the perfect performance. We did one mistake but we know very well against these opponents and players like Messi, Iniesta and Suarez, if you make a mistake you pay.
"It is a pity and we are disappointed with the final result.
"I don't remember a great save from Thibaut Courtois and they only had a couple of chances with Paulinho in the first half and Suarez in the second.
"I think we played a really good game and I must be pleased because my players gave a great effort and they followed the plan we prepared.
"In Barcelona we must be prepared to suffer together but at the same time when we suffer we must continue to try and get the chances to score."
Barcelona manager Ernesto Valverde said: "We gave too much space to Willian to shoot. The pass to him was perfect, the control was perfect.
"They might be happy with the result. They pressed us high and made it difficult for us but anything can change in the Nou Camp.
"The away goal isn't definitive but it is important."
Willian prolific outside the area - the stats
- Barcelona have conceded in each of their seven visits to Stamford Bridge in the Champions League (won one, drew two, lost four), with their only win coming in February 2006 (2-1).
- That win for Barcelona was the last time that Chelsea lost against the Spanish side, with the Blues unbeaten in their past eight Champions League games (won two, drew six).
- Six of Willian's nine Champions League goals for Chelsea have come from outside the box (67%).
- In fact, since joining Chelsea in 2013-14, Willian has scored more Champions League goals from outside the box than any other player (six, followed by Cristiano Ronaldo and Neymar on five).
- Messi has scored 18 goals in 27 appearances against English sides in the Champions League, including eight in his past five.
- Chelsea are the 71st club that Lionel Messi has scored against for Barcelona - he has only failed to score against 11 clubs that he has faced.
- Luis Suarez has now failed to score in the past 881 minutes of play in the Champions League, his longest drought in the competition. His last goal dates back to March 2017 against PSG.
Chelsea play three times before the second leg, including away Premier League matches against both Manchester sides. They visit Manchester United on Sunday, 25 February (14:05 GMT) and then Manchester City the following Sunday (16:00 GMT).
Barcelona are back in La Liga action on Saturday, 24 February with a home match against eighth-placed Girona.
- 2RüdigerBooked at 80mins
- 4FàbregasSubstituted forDrinkwaterat 84'minutes
- 11PedroSubstituted forMorataat 83'minutesBooked at 86mins
- 10E Hazard
- 1ter Stegen
- 15PaulinhoSubstituted forVidalat 63'minutes
- 4RakiticBooked at 29mins
- 5BusquetsBooked at 90mins
- 8IniestaSubstituted forAndré Gomesat 90+2'minutes
- 9SuárezBooked at 76mins
- 6D Suárez
- 21André Gomes
- Cüneyt Çakir
- Shots on Target
Second Half ends, Chelsea 1, Barcelona 1.
Hand ball by Álvaro Morata (Chelsea).
Sergio Busquets (Barcelona) wins a free kick in the attacking half.
Foul by Daniel Drinkwater (Chelsea).
Substitution, Barcelona. André Gomes replaces Andrés Iniesta.
Sergi Roberto (Barcelona) wins a free kick in the defensive half.
Foul by Eden Hazard (Chelsea).
Sergio Busquets (Barcelona) is shown the yellow card for a bad foul.
Foul by Sergio Busquets (Barcelona).
Eden Hazard (Chelsea) wins a free kick in the defensive half.
Delay over. They are ready to continue.
Delay in match Jordi Alba (Barcelona) because of an injury.
Luis Suárez (Barcelona) wins a free kick in the defensive half.
Foul by Daniel Drinkwater (Chelsea).
Álvaro Morata (Chelsea) is shown the yellow card.
Attempt missed. Victor Moses (Chelsea) right footed shot from outside the box misses to the left. Assisted by Willian following a set piece situation.
Foul by Samuel Umtiti (Barcelona).
Eden Hazard (Chelsea) wins a free kick in the attacking half.
Substitution, Chelsea. Daniel Drinkwater replaces Cesc Fàbregas.