The Welshman came close to scoring but in the end Arsenal succumbed to defeat.
Arsenal's Champions League campaign appears to be over. Despite a spirited display the Gunners were undone by a quick break from Barcelona and rash defending - with Lionel Messi the beneficiary of both.
Neymar burst away to square for Messi's first before Per Mertesacker's knockdown left substitute Mathieu Flamini in a world of trouble. He hacked down Messi before the Argentine brushed himself off and slotted home the penalty.
Arsenal had their chances, with German goalkeeper Marc-Andre ter Stegen making a stunning save from Olivier Giroud.
The German also stopped Aaron Ramsey from close range, with the Welshman unlucky not to be rewarded for his hard work.
The midfielder was one of Arsenal's best players on the night and that was a view shared by a former international team-mate.
Former West Ham United midfielder Jack Collison played for Wales with Ramsey and recently retired from the game.
He was watching the game and took to Twitter to pay tribute to Ramsey's performance in defeat:
The midfielder picked up a knock to his knee late on and ended the game limping. In the end his hard work and endeavour counted for nothing and with Arsenal two goals down going into the second leg in Spain there is surely no chance of a turnaround.