Atletico Madrid's La Liga dip has continued, losing 2-0 at home to Levante, allowing city rivals Real Madrid to cut the gap on the leaders.
Defending champions Madrid won 1-0 at Valladolid for a fourth consecutive win after Levante recorded their stunning away win at Atletico to move up to eighth.
The results left second-place Madrid within three points of Atletico, who still have a game in hand but are starting to feel the heat.
Third-place Barcelona can move within six points of Atletico if they beats strugglier Cadiz at home on Sunday.
Casemiro scored with a 65th-minute header off a free kick swung in by Toni Kroos to give Madrid the win, a fortnight before they visit Atletico in the El Derbi Madrileno.
Madrid have been able to inch closer to the top despite playing without several key players recently because of injuries, including Karim Benzema, Sergio Ramos and Eden Hazard.
None of the trio were available in Valladolid as Madrid withstood a few threats but were mostly in control against the hosts, who are second last in the 20-team standings.
"It was a great team effort as we have some very important players sidelined," midfielder Casemiro said.
"We are still fighting for the league title. We know it's difficult but there are still a lot of matches to be played."
Levante's Jose Luis Morales scored in the 30th minute and Jorge de Frutos added another goal in stoppage time, handing Atletico a first league loss since December and first at home in 14 months.
Diego Simeone's Atleti have won only one of their past four league matches.
"I'm not looking for excuses, we need to find solutions," Simeone said.
"It's natural that we will find difficulties along our path. There will be challenges."
Manu Vallejo and Kevin Gameiro scored a goal each in second-half stoppage time as Valencia beat Celta Vigo 2-0 at home to move to within two points of their 10th-place visitors.
Elche accounted for Eibar 1-0 at home with a first-half goal by Dani Calvo deciding the match between the relegation-threatened teams.