Ivan Rakitic scored a second-half winner as Barcelona defeated Athletic Bilbao 1-0 on Tuesday to leapfrog Real Madrid in the Spanish league.
Rakitic broke the deadlock in the 71st minute to move Barcelona three points ahead of Madrid, who on Wednesday host relegation-threatened Mallorca.
A win will see the lead change again as Madrid have better tiebreakers.
Rakitic scored less than 10 minutes after coming off the bench, firing a right-foot shot into the corner after an assist by Lionel Messi. It was Rakitic's first goal for Barcelona since March 2019.
Messi, who turns 33 on Wednesday, again wasn't able to score his milestone 700th career goal for club and country. He came close twice with shots that just missed the target late in the second half.
Barcelona were coming off a 0-0 draw at Sevilla, a result that allowed Madrid to take over the lead for the first time since the league resumed after the pandemic interruption.
Athletic, who have won only one of their three matches after the break, dropped to 10th.
Atletico Madrid extended their good run with a 1-0 win at Levante.
An own-goal by Bruno Gonzalez in the 15th minute gave Atletico their third straight win and moved Diego Simeone's team back into third place in the standings.
They are two points ahead of Sevilla, who had temporarily moved in front after a 2-2 draw at Villarreal on Monday.
Atletico were sixth when the league was interrupted by the coronavirus, but their winning run - coupled with a series of poor results from rivals - allowed them to quickly get back into the Champions League places.
"Happy for another victory and for these very important three points that take us closer to our goal of qualifying for the Champions League," Atletico midfielder Marcos Llorente said.
Gonzalez found his own net while trying to intercept a cross from Llorente to Diego Costa inside the area.
Atletico are six points clear of fifth-place Getafe, who drew 1-1 at Valladolid.