Julian Alvarez scored his 10th league goal of the season to help Atletico Madrid beat Athletic Club and move top of LaLiga.
The former Manchester City forward ran on to a superb defence-splitting ball by Marcos Llorente before calmly slotting in to break the deadlock in the 66th minute.
Athletic Club came agonisingly close to an equaliser when Benat Prados headed against the post and Inaki Williams crashed the rebound off the underside of the crossbar.
Diego Simeone's Atletico knew a win over the Bilbao side would see them jump above both FC Barcelona and Real Madrid, who lost to Real Betis earlier on Saturday (Mar 1).
However, their two-point lead could be short-lived, with second-placed Barcelona playing their game in hand against Real Sociedad on Sunday.
Atletico will hope they can rub more salt in the wounds of city rivals Real Madrid when they face each other in the first leg of the UEFA Champions League last 16 on Tuesday.
