Atletico Madrid squandered a chance to draw level on points with second-placed Barcelona when the champions slipped to a surprise 1-0 reverse at home to Villarreal in La Liga tonight.
Atletico dominated possession in a scrappy game but failed to convert what few openings they created and were undone when Villarreal forward Luciano Vietto cut inside his marker and drilled a shot past Miguel Angel Moya six minutes from time.
It was Atletico's first defeat in La Liga at their Calderon stadium since they were beaten by Barca in May 2013.
David Moyes’ first Basque derby at the helm of Real Sociedad ended in a 1-1 draw with ten-man Atletico Bilbao in San Sebastian.
Oscar de Marcos grabbed a 61st minute equaliser for Bilbao to cancel out former Arsenal striker Carlos Vela’s third minute header for the home side.
Bilbao were reduced to ten men in the 79th minute when defender Aymeric Laporte saw red after a second yellow card.
Sociedad rise one place in the table to 14th with 14 points while Bilbao stay in tenth spot on 19 points.
Real Madrid were the big winners in the 15th round of matches after Barca and fourth-placed Sevilla both drew and Real stretched their lead at the top to four points thanks to Friday's 4-1 success at Almeria.
Atletico forward Mario Mandzukic came close to breaking the deadlock against a well-organised Villarreal side when he drew a fine save from goalkeeper Sergio Asenjo with a close-range effort in the 56th minute.
The towering Croat nodded the ball in the net two minutes later but the referee ruled he had shoved defender Mario in the act of leaping for the ball.
Villarreal, who are sixth on 27 points, had looked dangerous on the break and Moya had to be alert to keep out a fierce Denis Cheryshev strike in the 82nd minute.
Argentina-born Vietto silenced the home fans two minutes later when he outpaced Atletico centre back Diego Godin and crashed the ball into the net.
Real, who are taking part in this week's Club World Cup in Morocco and are on a Spanish-record winning streak of 20 matches, lead on 39 points, with Barca on 35 after Saturday's 0-0 draw at Getafe.
Atletico have 32, two ahead of Sevilla. The Europa League champions' grip on Spain's fourth Champions League berth weakened when they were held to a goalless draw at home to top-flight debutants Eibar earlier on Sunday.
The result means Valencia are only two points behind Sevilla in fifth after they thumped visiting Rayo Vallecano 3-0 on Saturday.
Eibar, who have outperformed on their first appearance in La Liga despite a tiny budget, are ninth on 20 points.
Espanyol moved up to 11th on 17 points when Christian Stuani's 90th-minute strike secured a 2-1 win at home to Granada, who had midfielder Juan Carlos sent off eight minutes from time and are 16th.