Villarreal piled the pressure on under-fire Real Madrid coach Zinedine Zidane as they snatched a 1-0 win over the struggling La Liga champions at the Bernabeu.
Real reached the quarterfinals of the Copa del Rey -- where they will face Leganes -- in midweek, but started the day 16 points behind rivals Barcelona in the league.
And that massive gap remained in tact after a sublime finish from Pablo Fornals finished off an 87th-minute counter-attack from the Yellow Submarine, who had goalkeeper Sergio Asenjo to thank for a number of vital saves.
After Gareth Bale saw his header correctly ruled out for offside, Asenjo saved superbly from Marcelo's thunderous drive and Ronaldo's free kick, before also denying Ronaldo from close range on the stroke of half-time.
Asenjo made a number of more routine saves in the second period before the visitors cleared a late Real corner and set Denis Cheryshev clear down the left.
The half-time substitute found Enes Unal in the centre of the penalty area and, although Unal's shot was blocked by the onrushing Keylor Navas, it landed for Fornals to chip a first-time shot over the despairing goalkeeper.
Atletico Madrid were indebted to goalkeeper Jan Oblak as they closed the gap on Barcelona to six points with a narrow 1-0 win at Eibar.
The visitors scored what would prove to be the only goal of the game in the 27th minute when Antoine Griezmann cut the ball from the right towards Kevin Gameiro, who slotted past the on-rushing Marko Dmitrovic from close range.
Eibar, who were looking to break into the top six, went close to an equaliser just after the hour when Joan Jordan's header forced a brilliant save from Oblak.
The Slovenian was again alert with 11 minutes left to stop a header from Paulo Oliveira after a corner, and the instrumental Oblak again showed fine reactions to keep out a low effort from Takashi Inui.
In Saturday's late kick-off, third-place Valencia won 2-1 at Deportivo La Coruna to move eight points clear of Real Madrid.
Deportivo, battling at the other end of the table, almost took an early lead when Celso Borges' header hit the crossbar before Costa Rican then nodded another good chance over. It proved a costly miss as Valencia, who handed a debut to new signing Francis Coquelin from Arsenal, took the lead on 37 minutes following a blunder by Deportivo goalkeeper Ruben.
Goncalo Guedes tried his luck with an angled effort from 20 yards, which squirmed under the keeper at the near post and rolled into the net. Rodrigo added a second on 64 minutes with a deflected shot from the edge of the penalty area.
Florin Andone headed in a late consolation for the home side with three minutes left -- and there was still time for Adrian to fire over the crossbar as Valencia held out.
In the early kick-off, Michael Olunga scored a 22-minute hat-trick on an historic day for Girona as they thrashed bottom club Las Palmas 6-0 at Montilivi.
Kenya striker Olunga, who is on loan from Chinese club Guizhou Zhicheng, struck in the 57th, 70th and 79th minutes to become the first player to record a top-flight treble for Girona.
The win was also Girona's biggest in La Liga -- this season being their first in the division -- and most comprehensive victory in any competitive match in four years.
Cristhian Stuani's penalty midway through the first half was all that separated the teams at the interval, but Girona went to town after the break as Las Palmas crumbled to a 14th defeat in 19 league matches this term.
Borja Garcia (64 minutes) and Cristian Portu (74) were Girona's other scorers.