Lionel Messi netted two late goals as champions Barcelona thrashed Sevilla 4-0 to stretch its advantage over second-placed Real Madrid at the top of La Liga to five points.
Real had earlier slumped to a 1-0 defeat at Athletic Bilbao, goalkeeper Gorka Iraizoz pulling off a string of superb saves to deny the visitors' expensively-assembled strikeforce after Fernando Llorente's third-minute opener.
With just under half the season gone, unbeaten Barca has 46 points from 18 matches, Real is on 41, and Valencia, which hosts local rival Villarreal tonight, is third with 35.
"Athletic are a very strong side and they knew very well how to defend the lead they managed to get so early in the game," Real coach Manuel Pellegrini said.
"We had five or six clear chances but we lacked precision and were missing a bit of luck.
"There is a long way to go in the league and there are 60 points still to play for so nothing is decided."
Holders Barca were ousted from the King's Cup by Sevilla mid-week and Pep Guardiola's players looked hungry for revenge at a rainy Nou Camp.
Zlatan Ibrahimovic, Thierry Henry and Messi all went close before Sevilla defender Julien Escude diverted a Rafael Marquez cross high into his own net in the 49th minute.
A perfectly weighted, defence-splitting pass from midfielder Xavi released substitute Pedro with 20 minutes left and his delicate chip beat advancing Sevilla goalkeeper Andres Palop.
Messi, who grabbed a hat-trick at promoted Tenerife last weekend, finished from close range in the 85th and then raced on to an Eric Abidal pass in the first minute of added time to score his 14th goal of the campaign, two more in the scoring charts than nearest rival David Villa of Valencia.
In the early kick-off, Juanfran and Walter Pandiani struck inside the first 10 minutes to give Osasuna a 2-0 home win over Espanyol that lifted the Pamplona-based club to 12th.
Frustrating night
Shell-shocked Real was behind early when Lassana Diarra could only head a Fran Yeste corner into the path of Llorente and the unmarked striker stooped to nod the ball past keeper Iker Casillas.
Karim Benzema, Cristiano Ronaldo and Kaka - who together cost Real almost 200 million euros ($289 million) in the close season - had numerous chances to level.
France forward Benzema came closest when his low shot bounced back off the inside of the post in the 34th minute.
Iraizoz made his best save of the match in the first minute of added time when he flung himself acrobatically to tip away a powerful Ronaldo drive.
The Portugal forward ended a frustrating night when he sent a free kick sailing over the bar into the jubilant home crowd.
Source: ABC Sport