Arsenal playmaker Samir Nasri started tonight's Champions League last-16, first leg against Barcelona at the Emirates Stadium, but it was Robin van Persie and Andrey Arshavin who gave the Gunners their two goals.
Nasri, the Gunners' top scorer with 14 goals, made his first appearance since January 30 after recovering from a hamstring injury.
Robin van Persie started up front, supported by Nasri and Theo Walcott, while the suspended Bacary Sagna was replaced by Emmanuel Eboue and goalkeeper Wojciech Szczesny made his Champions League debut.
Barcelona, viewed by Arsene Wenger as the best team in the world, included Lionel Messi, Xavi, Andres Iniesta and David Villa in their side.
Nasri produced a dangerous early touch when he snaked a free-kick into the box, but Arsenal could not get a foot on the ball.
The Gunners looked anything but intimidated by their opponents' reputation as Walcott sped through the midfield, only for his final pass to overrun van Persie.
Moments later Walcott threaded his way across the penalty area, evading several defenders as he ran, before finding an unmarked Cesc Fabregas.
The skipper lifted the ball to van Persie who forced a fine save on the half-volley from Victor Valdes from a tight angle.
Alex Song was booked for bringing down Messi and the Argentina forward then tumbled to the floor, the victim of robust defending.
Arsenal's rearguard was far less convincing in the 15th minute, however, when Iniesta put Messi through on goal.
Messi had timed his run perfectly, leaving Laurent Koscielny and Johan Djourou stranded, but with only Szczesny to beat he steered his shot wide of the post.
It was a massive let off for the Gunners, who found themselves being pushed back with increasing regularity as Messi directed a good chance straight at Szczesny.
Once again Walcott tore through Barcelona's midfield, picking out Fabregas, but the Spaniard's cross was cleared just before Van Persie could connect.
The visitors had been threatening a goal, however, and it arrived in the 27th minute through David Villa.
It all looked so easy as Messi slid a perfect pass through to Villa and the Spain striker expertly sent his shot past Szczesny.
Villa caused panic shortly after as Barcelona renewed their assault, but this time Arsenal escaped as Szczesny was able to snatch the ball.
Respite was offered by a dynamic run from Jack Wilshere, but the move ended when Van Persie took one touch too many before unleashing his shot.
Messi scrambled the ball into the net as half-time approached but the flag had been raised for offside.
Arsenal finished the half with a flourish by launching a series of raids, the best of which saw Van Persie send a looping header over the crossbar.
INTRO: David Villa fired Barcelona into a half-time lead in tonight's Champions League last-16, first leg clash with Arsenal.
Villa tucked home a perfectly-weighted pass from Lionel Messi in the 27th minute.
Barcelona would have been further ahead had Messi not missed a sitter, while Robin van Persie failed with Arsenal's best chance.
Arsenal made a bright start to the second half with Wilshere just failing to get enough power on his shot to trouble Valdes.
For all their brilliance on the ball, Barcelona were working hard when not in possession, while the Gunners were often guilty of not committing enough players to the attack.
Walcott found space to roam down the left but Sergio Busquets intercepted as Van Persie was about to pounce.
There was greater energy about Arsenal now as they staged a series of attacks, though their cause was not helped when Fabregas sent a free-kick into the arms of Valdes.
Nasri threatened at the near post but Gerard Pique arrived to bundle his cross into touch before Van Persie could connect, while moments later the Dutchman was kept out by Valdes.
Arsenal suffered a scare in the 68th minute when Eboue let Messi creep free but the Argentinian hit the sidenetting instead of squaring to the line of team-mates queuing up to pounce.
Arsenal continued to press as the game became increasingly open and in the 79th minute their endeavour was rewarded.
Gael Clichy did the initial damage with a superbly-lofted ball down the left channel that was gathered by Van Persie.
The Holland marksman was at an impossibly tight angle but his powerful shot slipped inside Valdes at the near post.
It was a poor piece of goalkeeping from Valdes, but he could do nothing about the winner that arrived with six minutes to go.
Revelling in the space now available to them, Arsenal burst free down the right as Nasri raced onto a brilliant pass from Fabregas.
Andrey Arshavin, who had replaced Walcott, arrived on the edge of the area to pick up the Frenchman's pass before burying the ball in the back of the net.
Arsene Wenger celebrated deliriously on the sidelines and Arsenal survived a furious late assault to secure a tantalising glimpse of the quarter-finals.
INTRO: Robin van Persie and Andrey Arshavin struck in the second half as Arsenal staged a brilliant late comeback to give them hope of progressing in the Champions League.
David Villa fired competition favourites Barcelona ahead in the first half after combining with Lionel Messi.
But their superiority faded in the second half when Arsenal took control, with Van Persie starting the comeback in the 79th minute before Andrey Arshavin smashed home the winner.