Barcelona lost Lionel Messi to another leg injury but still had more than enough firepower to beat Real Betis 4-1 and capitalize on a stumble by title rival Atletico Madrid on Sunday.
Things looked grim for the defending champions when Messi suffered his third leg injury of the season and asked to be substituted in the 21st minute, as Barcelona came under pressure.
Barcelona said that Messi had a "muscle injury in his left thigh" and that he would undergo medical tests on Monday.
But Cesc Fabregas scored two goals and made another in a convincing victory.
Goalkeeper Victor Valdes made two superb saves to deny Jorge Molina before Fabregas set up Neymar for Barcelona's 35th-minute opener.
Pedro Rodriguez made it 2-0 two minutes later, and Fabregas finished off the scoring for Barcelona in the 63rd and the 79th minutes.
Atletico Madrid stumbled to a 1-1 draw at Villarreal after both sides conceded own goals.
Atletico went ahead just two minutes into the match at El Madrigal Stadium when Juanfran Torres broke free on the right flank and swung in a cross that defender Mario Perez turned into his own net while trying to fend off Koke.
Atletico held Villarreal's passing attack in check until coach Marcelino Garcia sent on striker Jeremy Perbet. Five minutes later, Perbet provided the missing spark when he collected the ball from a throw-in, dribbled into the area and provided a square pass that Juanfran ended up poking into his own goal while jostling with Villarreal's Ikechukwu Uche.
Villarreal is in fourth place, but seven points behind Real Madrid in third.
Earlier, Sevilla beat Espanyol 3-1 to end a 22-game winless run away from home in the league.
Sevilla dominated at Cornella-El Prat Stadium from the start, with Federico Fazio outmaneuvering Sidnei to head in Ivan Rakitic's free kick three minutes in.
Vitolo Machin scored from a corner for Sevilla in the 10th minute before Espanyol forward Sergio Garcia pulled one back in the 24th.
But Sevilla striker Carlos Bacca secured all three points in the 58th minute with a solo effort after beating two Espanyol defenders. The Colombian surged past Hector Moreno before knocking the ball beyond Juan Fuentes and running around him to reach it fire into the net.
Espanyol finished with 10 men when Victor Sanchez received his second booking with five minutes to play.
Valencia were held to a 2-2 draw by Valladolid to remain without a victory in their past three home games.
Valencia's Ever Banega missed a penalty in the fourth minute, sending his spot kick high over the top after Valladolid goalkeeper Diego Marino had cut down Antonio Barragan in the box.
Striker Javi Guerra headed Valladolid in front in the ninth minute before Dorlan Pabon made it 1-1 in the 29th with a long-range strike that took a slight deflection off another player to catch Marino out of position.
Gilberto "Alcatraz" Garcia, who had set up Guerra's opener, drilled in Valladolid's second goal from a tight angle in the 50th, only for Sofiane Feghouli to guide home a cross by Sergio Canales in the 76th to cap a rare counterattack by Valencia.