Barcelona striker David Villa celebrates after scoring against Deportivo
The Argentine World Player of the Year, who is up against team mates Xavi and Andres Iniesta for the FIFA Ballon d’Or on Monday, swept in a freekick in the 51st minute, having already set up striker David Villa for the opener in the first half.
Iniesta made it 3-0 from the edge of the area in 80th and almost immediately Messi’s driving run led to the ball breaking to Pedro, who lifted the ball into the net for the fourth.
The champions maintained their perfect away record in La Liga to move on to 49 points from 18 games, putting the pressure on chasing Real Madrid, who host third-placed Villarreal at the Bernabeu on Sunday.
Earlier, two goals in three minutes from Luis Fabiano and Frederic Kanoute helped Sevilla fight back to win 3-2 at promoted Real Sociedad.
The result, Sevilla’s fourth straight victory in all competitions, helped lift Gregorio Manzano’s improving side up to ninth with 26 points from 18 games.
They are behind Athletic Bilbao on goal difference after the Basque side drew 1-1 at Malaga.
Mali striker Kanoute volleyed Sevilla level in the 25th minute, soon after Diego Rivas had opened the scoring at Anoeta, but Joseba Llorente put the home side back in front with a breakaway goal after hesitant defending just before halftime.
Brazilian striker Fabiano poked the ball home from close range after a corner in the 63rd to level the scores again and Kanoute fired in a off the post soon after to seal the win.
Bilbao’s Javi Martinez headed a 93rd-minute equaliser in off the post to deny Malaga at the Rosaleda.
Argentina defender Martin Demichelis, one of four new Malaga signings on show, had marked his league debut with a glancing header from a corner in the 81st to give the hosts the lead.
Malaga remain in 16th place with 17 points, now four points above the relegation places.