Four-goal Messi stuns Valencia
Valencia took a surprise lead through Pablo Piatti in the ninth minute, but Barça's response was composed and clinical as they tore the visiting defence apart, producing chance after chance as Messi scored twice before half-time and then twice more in the final 15 minutes. He then found time to help set up Xavi for a fifth in injury time.
Barça began brightly and the pressure soon told as David Albelda was booked in only the fourth minute for bringing down Messi on the edge of the box.
Despite his efforts, Valencia took the lead when Sofiane Feghouli stood up a cross and a mix-up between Gerard Pique and Martin Montoya, standing in for Dani Alves, allowed Piatti to break free and score easily. But the hosts responded with a string of attacks as they produced some breathtaking football.
They were level in the 22nd minute when Adil Rami and Victor Ruiz collided trying to deal with Pedro's low cross and Messi picked up the pieces to finish from a tight angle. Valencia also lost Miguel to an injury in the build-up and he was carted off.
Ruiz made a fine block as Messi looked to shoot following a run from the halfway line, and minutes later the second goal came.
Andres Iniesta played a defence-splitting pass to find the run of Eric Abidal, who crossed for Messi at the far post. Diego Alves got down well to save his shot, but spilled the ball and the Argentinian blasted the rebound high into the net and make it his 40th goal of the season.
Barcelona continued to pile forward, with Alves denying Alexis Sanchez after Cesc Fabregas' pass set him free. Fabregas himself then tested the goalkeeper after racing into the box, before Messi found the side-netting after great link-up play with Iniesta.
Fabregas almost scored a wonder goal when he met Iniesta's chipped pass with a volley on the turn, but his effort came back off the underside of the crossbar.
Valencia saw Ricardo Costa, the replacement for Miguel, limp off before returning somewhat hobbled, while Messi was denied a first-half hat-trick when the ball was picked off his toe following a one-two with Pedro.
Barça's pressure resumed in the second half, with Fabregas' shot turned wide before Pedro had the ball in the net, only to be denied by an assistant's flag. Iniesta curled an effort inches away from the top corner, while Messi then saw his point-blank header pushed onto the crossbar from Montoya's cross.
Fabregas missed a sitter when Barcelona broke, failing to cap a move he started with a fine pass to Montoya. The full-back's shot was saved by Alves straight into the path of the former Arsenal midfielder, but he blazed well over.
Victor Valdes had been a spectator throughout the second half, but made a brilliant save in the 67th minute from Feghouli's snapshot through the crowd. However, Messi's sixth hat-trick came in the 75th minute to put the game to bed.
The Argentinian found the run of Cristian Tello, and then lashed in the rebound when Alves could not hold the substitute's shot. Pique and Tello both shot over before Messi capped an outstanding night five minutes from time, scoring his 146th goal in 200 league games for Barça when he latched on to Sergio Busquets' through-ball and nonchalantly chipped over Alves.