Atletico Madrid will stay top of La Liga until at least the weekend after beating Real Sociedad 2-0 on Tuesday to move three points ahead of the chasing pack.
Second-half goals from Mario Hermoso and Marcos Llorente earned Diego Simeone's side a huge win away at a Sociedad team that started the fixture three points off the lead but are now six back in third after their third straight league defeat.
Champions Real Madrid, who sit second, can move level again with their city rivals with a home win over Granada on Wednesday.
Barcelona meanwhile are 11 points behind Atletico in sixth place ahead of their clash with Real Valladolid later on Tuesday.
After tomorrow's games, Real and Barcelona will have played two more matches than Atletico. Sociedad have played three games more than the leaders.
The win was Simeone's 300th league win as Atletico coach.
"It's means a lot, really a lot," the Argentine said.
"I came here with the idea of taking Atletico to the summit of the game ... I can't thank the club enough for what they have given me."
Sociedad were the better side in the first half but couldn't carve a goalscoring opportunity in an opening period without a shot on target.
Atletico went ahead just three minutes after the break when Hermoso found himself unmarked in the area and perfectly met Yannick Carrasco's free-kick to send a header flying into the bottom corner.
The hosts responded by pressing their opponents back but couldn't find a way through a typically well-organised Simeone team.
Atletico doubled their lead with 16 minutes remaining, Llorente lashing home when the ball fell to him on the edge of the area.
Earlier Sevilla moved up to fifth after Suso fired them to a 1-0 win at struggling Valencia.
Suso gave the Andalusians the points with a thumping strike in the 81st minute after charging through to collect a Joan Jordan through ball.
The winning strike was the 27-year-old Spain international's first goal of the season.
Sevilla are nine points behind Atletico but two points in front of Barca.
Valencia are 13th and just a point above the relegation zone after their sixth consecutive league match without a win.