Atletico Madrid moved three points clear at the top of La Liga thanks to victory at third-placed Real Sociedad.
Mario Hermoso’s header broke the deadlock early in the second half before Marcos Llorente’s cool finish sealed victory for Diego Simeone’s men.
Atletico, who have conceded just five goals in 13 league games this term, comfortably kept an eighth clean sheet.
Real Madrid could draw level on points if they beat Granada on Wednesday but will have played two games more.
Zinedine Zidane’s Real are the only side to have inflicted a domestic defeat on Atletico this season and Sociedad rarely looked like becoming the second.
Their only shot on target came late on and Atletico keeper Jan Oblak was equal to Martin Merquelanz’s strike from just outside the box to preserve the visitors’ impressive defensive record.
Central defender Hermoso went close with a first-half header before nodding Atletico ahead from Yannick Carrasco’s cross after the break for his first league goal for the club.
Llorente then fired home left-footed strike to extend Sociedad’s winless run to six games after a promising start to their season.