Atletico Madrid moved four points clear of local rivals Real Madrid with a 1-0 win in the Bernabeu on Saturday.
Antoine Griezmann scored the only goal eight minutes after half-time. The France star advanced unchallenged to the edge of the box and looked set to shoot, instead feeding Filipe Luis on a breakneck overlap and then converting the full-back's return pass.
Real dominated possession but could not test visiting keeper Jan Oblak severely enough and were denied a second-half penalty when Danilo went down under Gabi's challenge.
Zinedine Zidane's first defeat as Real coach means they remain nine points behind leaders Barcelona in third place in La Liga.
Real are dealing with a number of injuries to top players, and Cristiano Ronaldo was strongly critical of his teammates after the match.
"I don't want to say that Jese, Lucas [Vazquez] or [Mateo] Kovacic are not good players -- they are very good, but ... to win a competition you need to have your best players," he said.
Celta Vigo moved level on points with fifth-placed Sevilla, who play Barcelona on Sunday, with a 1-0 win over Getafe.
Nolito scored the only goal, his first for three months -- much of which has been spent on the sidelines with a torn hamstring.
Espanyol came from behind to beat fellow strugglers Sporting Gijon 4-2 and record consecutive league victories for the first time since September.
Carlos Castro gave the hosts the lead but Espanyol winger Burgui scored a spectacular equaliser and Gerard Moreno's double put them in control.
Castro netted again but teammate Luis Hernandez then scored an own goal before Nacho Cases was sent off.
Manucho fired a second-half double as Rayo Vallecano fought back from two goals down to draw 2-2 at Real Betis.
The Angola international, a half-time substitute, struck twice within six minutes of the second half to cancel out Ruben Castro's first-half brace for Real Betis as Rayo extended their unbeaten league run to seven matches.
Betis almost snatched it in stoppage time when midfielder Dani Ceballos' shot hit a post, but the visitors were worthy of a point.
Real Sociedad came from behind to salvage a 1-1 draw with Malaga in the day's final match, with Imanol Agirretxe cancelling out Duje Cop's opener.