Thierry Henry opened the scoring on 19 minutes with an unstoppable shot, and Lionel Messi added the second goal one minute past the half hour mark with a superb clinical finish.

Seconds later, Diego Forlan released a fierce drive to pull one back for the home side, and Aguero canceled out Barcelona's slender lead ten minutes after the interval, thanks to a Rafael Marquez blunder.

Henry fired the visitors ahead once again on 72 minutes when he was fed by Eidur Gudjohnsen, but Forlan brought the score level upon converting a spot kick 10 minutes from time.

One minute from time, Aguero steered home to beat Victor Valdes and stun the visitors.

Barcelona now are four points clear at the top of the league. Second-placed Real Madrid have 56 points, following their victory over Espanyol.

In other matches on Sunday, Valencia lost 2-1 at home to Real Valladolid while Villarreal and Real Betis played out a 2-2 draw.