Barcelona returned to the top of the Spanish league on goal difference after Robert Lewandowski's first-half penalty secured a 1-0 win over Rayo Vallecano.
The Catalan club on Monday took advantage of weekend slip-ups by Real Madrid and Atlético Madrid to move onto 51 points, the same as Madrid and a point clear of Atlético.
Madrid drew 1-1 at Osasuna on Saturday and Atletico was held by the same score at home by Celta Vigo.
Barcelona took the lead after 27 minutes when Pathe Ciss brought down Íñigo Martínez in the box, and a penalty was awarded after a video review. Lewandowski sent the keeper the wrong way from the spot.
Both sides had chances to score after that.
Augusto Batalla saved well from Lamine Yamal, who was playing the 100th game of his career, while at the other end Jorge De Frutos had the ball in the net for Rayo only to see it ruled out for offside.
De Frutos was always dangerous for Rayo but as the game went on the home side took control as it extended its unbeaten run to 12 matches.
The defeat ended Rayo nine-game unbeaten streak that stretched back to Dec 7.
