Sergio Ramos and Karim Benzema scored second-half goals as Real Madrid beat Real Sociedad 2-1 to take the lead from Barcelona for the first time since the Spanish league resumed.
Ramos converted a 50th-minute penalty kick and Benzema added to the lead in the 70th to move Madrid ahead of the Catalan club, which on Friday was held by fourth-place Sevilla to a 0-0 draw.
Madrid and Barcelona are level on 65 points, but Madrid has a better goal difference and a better head-to-head record against its rival.
Madrid had led five of the last seven rounds before the break, but Barcelona went in front just before the league was suspended due to the coronavirus pandemic more than three months ago.
Barcelona had stayed ahead after two straight victories since the league restarted. The defending champions have eight rounds left to try to retake the lead.
Madrid kept its perfect record on its return despite a lackluster first half at Sociedad. Ramos broke the deadlock from the penalty spot after Vinícius Júnior was fouled, and Benzema sealed the victory from inside the area for his third goal after the break.
The French striker, who had a double in the team's 3-0 win over Valencia on Thursday, reached 17th league goals, four behind scoring leader Lionel Messi.
Sociedad had a goal disallowed for offside just before Benzema's goal. Mikel Merino eventually pulled the hosts closer in the 83rd with a shot that struck the crossbar before going in, but Sociedad was not able to get the equaliser.
It was the third straight setback for Sociedad since the league resumed, dropping the Basque Country club to seventh place. It had returned from the break in fourth place, the final Champions League spot.
Ramos was substituted 10 minutes after scoring. He had needed medical assistance a few moments earlier for an apparent knee injury.
Colombia midfielder James Rodriguéz made his first start for Real Madrid since October. He was substituted in the 78th.
Celta Vigo earned its first win after the break with a 6-0 rout of 10-man Alavés.
Rafinha scored twice and newly signed striker Nolito added another on his return to Celta, which was coming off a draw and a loss after the league resumed.
Jeison Murillo, Iago Aspas and Santi Mina completed the scoring to lift Celta four points clear of the relegation zone.
Alavés, which dropped to 13th, played most of the match with 10 men as Martín Aguirregabiria was sent off with a straight red card for a hard foul in the 27th minute. The visitors were losing 4-0 by halftime.
Nolito, who converted a penalty kick in the 78th, was signed from Sevilla last week to replace the injured Sergio Álvarez after league approval was given. Nolito played for Celta before he was signed by Manchester City in 2016.
Valencia also ended its post-break slump with a 2-0 home win against Osasuna, moving closer to the European spots.
Gonçalo Guedes opened the scoring with an impressive goal after getting past several defenders and sending a shot into the top corner in the 12th. He then set up the second with a long pass for Rodrigo's touch from inside the area in the 35th.
Referee David Medié needed medical assistance early in the second half after colliding with an Osasuna player. He fell to the ground but was able to continue.
Valencia is in eighth place. Osasuna, still winless after the break and coming off a 5-0 home defeat against Atlético Madrid, is 12th.
Milan: Soccer resumed in one of the Italian cities hit hardest by the coronavirus pandemic with a poignant Serie A match as Atalanta gave a much-needed boost to the residents of Bergamo.
Atalanta beat Sassuolo 4-1 in its first Serie A match in 112 days and the first in Bergamo since Feb. 15. "There's a lot going on in the world and Bergamo has been hit hard. This win was for the city, the people, the club. The worst days are behind us, change is coming," Atalanta midfielder Marten de Roon wrote in a post on Twitter after the match.
More than 16,000 people have died from the virus in the Lombardy region containing Bergamo, and the small city was one of the epicenters of the outbreak.
Images of a convoy of military trucks driving coffins out of the city because the crematorium couldn't keep up were beamed around the world.
Romelu Lukaku marked his goal by taking a knee.
Lukaku, who is Black, showed his support for the Black Lives Matter movement after scoring Inter's opener in the 10th minute, finishing off an impressive team move.
Lautaro Martínez doubled Inter's lead before Morten Thorsby pulled one back for Samp eight minutes into the second half.
Third-place Inter moved six points behind leader Juventus and five below second-place Lazio. Sampdoria remained a point above the relegation zone.
Sampdoria was one of the teams which announced the highest number of cases of COVID-19, including at least seven players, with the team doctor hospitalized.
Inter's team doctor was also hospitalized with the virus.