Arsenal came off the ropes to secure a 2-2 draw with Barcelona that kept their Champions League dream alive in the most unlikely fashion on an exhilarating night at the Emirates.
Having completely outclassed their hosts for much of the first half, the defending champions appeared to be cruising into the last four after two goals from Zlatan Ibrahimovic in the early stages of the second period.
But Theo Walcott’s strike and a late penalty from Cesc Fabregas set the stage for a tension-filled second act in the Nou Camp next week.
Barca will be without both their first-choice centrebacks for the return leg with Gerard Pique, who was booked here, and Carles Puyol, who was sent off for the foul on Fabregas that led to Arsenal’s equaliser, both ruled out by suspension.
Arsenal will scarcely be in better shape however with Fabregas also suspended after picking up a booking here and William Gallas and Andrey Arshavin both forced off with injuries.
From the outset it was clear that Lionel Messi, Xavi and co. regarded the wide spaces and immaculate surface of the Emirates as an invitation to party.
For more than 20 minutes, the home side was restricted to the exhausting pursuit of shadows that is more commonly the lot of visitors to north London.
That Arsenal survived the torrid opening unscathed was largely down to Manuel Almunia, who threw himself full length to deny Sergio Busquets, deflected a Messi effort over the bar with his legs and then pushed out a strong left-hand to deny Ibrahimovic, blocking Xavi’s follow-up for good measure.
Profligacy also contributed to the lack of a breakthrough, notably from Ibrahimovic, who lifted a sixth minute chance over the the bar from the edge of the six-yard box and then found the side netting after Thomas Vermaelen’s slip had allowed him to run clear of Arsenal’s back four.
Arsenal conjured up their first moment of menace in the 23rd minute, Samir Nasri sidestepping Daniel Alves on the corner of the penalty area before curling a shot narrowly beyond the far post with Victor Valdes, the Barca goalkeeper, struggling to cover.
There was also a reminder of Barcelona’s vulnerability in the air when Nicklas Bendtner got free on the right and sent in a cross that Abou Diaby, having outjumped Gerard Pique, nodded wide.
There was a palpable sense of relief among the home supporters that their team reached the interval on level terms.
Within 30 seconds of the restart however, Barcelona were in front thanks to a Pique punt that caught both Alex Song, who had been redeployed to centreback following the exit of Gallas, and Almunia badly out of position.
Allowed a free run through the inside right channel, Ibrahimovic had his mind made up for him by Almunia’s charge off his line and duly lifted the ball over the goalkeeper.
Only a superb stop from Valdes prevented Bendtner from heading Arsenal back into the contest after a fine cutback from Gael Clichy.
But it was no surprise when Barca extended their lead shortly afterwards. Xavi was the instigator, clipping a delicate through ball into the area and Ibrahimovic produced an emphatic finish to beat Almunia at his near post.
Wenger’s response was to throw Walcott into the fray and the England winger’s introduction yielded an almost immediate result that will have been noted by the watching Fabio Capello.
Typically neat build-up work culminated in Bendtner playing Walcott in behind Puyol and the winger’s shot managed to slither under Valdes’s dive.
Arsenal had secured a lifeline and they took a firmer grip on it with five minutes left after Fabregas, attempting to latch on to a Bendtner knockdown, was impedged by Puyol.