Argentine Messi showed why he is regarded as the world's best player with three terrific individual second-half goals earning him a standing ovation at the Camp Nou as Barca moved three points clear of Real Madrid.
Messi's first after 56 minutes was the pick of the bunch combining speed, dribbling and trickery as the 22-year-old led three defenders a merry dance before slotting home.
With Valencia down to ten men after the dismissal of defender Hedwiges Maduro on 69 minutes Messi ran riot scoring an 81st minute left-footed curler and a deft chipped effort with his right foot a minute later.
After a summer investment of over 250 million euros much more was expected but now all Real can do is win the league title and even that may not save the job of under-fire coach Manuel Pellegrini.
Barca are still in the Champions League and face VfB Stuttgart in the Champions League last 16 second leg at Camp Nou on Wednesday with the score at 1-1 from the first leg.
For third-placed Valencia this was a fifth defeat of the season and they lie a full 18 points behind leaders Barcelona.
Valencia were without top-scorer David Villa, with 17 goals to his name this season, through a shoulder injury so Argentine Chori Dominguez started in his place.
Barcelona coach Pep Guardiola, watching from the stands as he serves a touchline ban, breathed a sigh of relief.
The visitors were closing down the home side well but Messi began to cause havoc forcing a save from Cesar Sanchez after 34 minutes.
Messi then showed incredible control before accelerating past two defenders and releasing Pedro who dragged his shot wide.
A minute later Valencia were reduced to ten men when Dutch defender Maduro collected a second yellow card for fouling Messi.
Messi had his revenge by bagging two more goals, meaning he is five ahead of Villa at the top of the goalscoring charts.
Villarreal closed to within six points of the top six enhancing their hopes of qualifying for the Europa League with a 2-0 home win over Xerez at El Madrigal on Saturday.
Source: AFP Global Edition