Arshavin finished off a swift Arsenal move for the winner
The Catalans wasted chances to strengthen their position, with Lionel Messi an unlikely culprit, leaving the door open for the Gunners to keep their hopes of reaching the quarter-finals alive in spectacular fashion.
Robin van Persie equalised 12 minutes from time with a shot that somehow eluded Barcelona keeper Victor Valdes at his near post before substitute Andrey Arshavin sent Arsenal's fans into ecstasy with a crisp finish that gives them a slender lead to take to Spain.
The Premier League outfit were attempting to follow in the footsteps of arch-rivals Tottenham after their magnificent win against AC Milan in the San Siro on Tuesday - and they were not to be outdone as they made it a memorable 24 hours for north London in Champions League combat.
Lionel Messi suffered a frustrating night in north London
Barcelona were suddenly rocking and Wenger's team turned the tie on its head and, roared on by feverish backing on a thunderous night, scored the winner when Arshavin arrived on the end of Nasri's right-flank cross to steer a precise finish past Valdes.
Arshavin showed the other side of his game when a moment of defensive vulnerability almost let in Dani Alves in stoppage time - but Arsenal survived to keep their Champions League hopes alive.
