Pep Guardiola's side come from behind to claim three points at Camp Nou after humbling Unai Emery's men
Save for a shaky opening 10 minutes, the hosts were in charge for the majority of the match, and perhaps should have won by a bigger margin but found themselves facing an in-form Diego Alves, who made a number of world-class stops throughout the game.
Valencia got off to a flyer and went ahead in the ninth minute when Pablo Piatti took advantage of some indecision in the Barcelona defensive ranks to give Valencia the lead.
Sofiane Feghouli was given all the space in the world on the right wing to whip a cross into the centre of the box, where Piatti drifted in between Puyol and Busquets to poke the ball home after getting in front of the on-rushing Victor Valdes, who had lost the flight of the ball.
The Catalans started to find their feet as the first half progressed, and equalized in the 22nd minute through Messi, who was making his 200th La Liga appearance for Barcelona.
Pedro was the architect, and showed electric pace down the left to drive forward and slide a pass into the box. Messi picked up the ball after Adil Rami failed to clear and showed fantastic composure to slip the ball past Diego Alves from a tight angle.
The Argentine grabbed his second goal of the game just five minutes later when Andres Iniesta threaded a wonderful pass in behind the Valencia defense for Eric Abidal who picked out Messi at the far post. Alves made a great save from the first shot, but the Barca maestro stabbed home the rebound into the roof of the net.
The quarter of an hour after break was all Barcelona, who would have went 3-1 up if not for a truly magnificent save from Alves. Alexis Sanchez clipped a cross into the box for Messi to power a header at goal, but the Valencia goalkeeper somehow tipped the ball onto the crossbar, to add to an already impressive array of saves in the match.
Messi netted his hat-trick goal 15 minutes from time when he latched on to a saved Cristian Tello shot to smash the ball home from 12 yards an give Barcelona a commanding lead.
The Argentine got out the party tricks for the rest of the game, and scored an incredible fourth goal of the match five minutes from time when he drove through on goal and masterfully lifted the ball over Alves, and received a standing ovation from the majority of the Camp Nou crowd.
Xavi was introduced five minutes from time an completed the rout in the last minute of the match with a strike similar to the fourth goal, in which the substitute delightfully lifted the ball over Alves from 12 yards.
Barcelona remains in second place in La Liga 10 points behind Real Madrid, but further distances itself from Valencia in third place, with an 11 point gap between the sides having been established this evening.