Third-placed Valencia let a lead slip away for the fourth consecutive home game as Arouna Kone's second-half strike earned local rivals Levante a 1-1 draw at Mestalla.
Jonas Goncalves rounded off a fine team move to give the hosts the lead 10 minutes before half-time, but Levante were level eight minutes after the break as Valdo headed Jose Barkero's cross into the path of the Ivorian who rifled home his 11th league goal of the season.
Both sides had great chances to win the game in the final 10 minutes as Kone stabbed Pedro Botelho's cross inches wide before substitute Paco Alcacer headed straight at Gustavo Munua with the goal at his mercy.
Valencia have now only won once in six league matches at home in 2012.
Elsewhere on Sunday, Diego scored on his first start for seven weeks as Atletico Madrid cruised to a comfortable 3-0 win over Getafe.
Eduardo Salvio put the hosts in front midway through the first-half as he brilliantly looped a header over Miguel Angel Moya from Filipe Luis' cross.
Diego then made it two just after the hour mark as his initial header off the bar rebounded kindly for him to tap home at the second attempt, and Radamel Falcao wrapped up the three points 13 minutes from time with another calm finish from Juanfran's cross.
Villarreal barely helped their relegation fight following a forgettable goalless draw against European hopefuls Espanyol at El Madrigal.
Both sides had the ball in the net, but both were ruled out for questionable fouls.
Marco Ruben thought he had scored for the hosts in the first half when he poked in after Espanyol goalkeeper Francisco Casilla fumbled only for the referee to whistle.
Villarreal then thought they had a penalty for a foul on Borja Valero before Espanyol were denied when Raul Rodriguez's finish was ruled out for an earlier foul on Diego Lopez.
Real Sociedad returned to winning ways in emphatic style with a thumping 4-0 home victory over Rayo Vallecano that could prove vital to their hopes of staying up.
A run of four defeats in five games had seen Sociedad slip ever closer to the relegation zone but they earned a priceless three points against mid-table Rayo thanks to goals from Imanol Agirretxe, David Zurutuza, Antoine Griezmann and Carlos Vela.
Real Madrid continue to boast a six-point lead over Barcelona at the top of the standings after both sides claimed impressive wins on Saturday evening.
Madrid brought up 100 league goals for the season in their 30th match after thumping sixth-placed Osasuna 5-1.
Ronaldo took his own tally to 37 for the league campaign with a brace, while Gonzalo Higuain also netted twice after Karim Benzema had given Jose Mourinho's title-chasers a seventh-minute lead.
Osasuna, who saw coach Jose Luis Mendilibar sent to the stands early on and substitutte Roland Lamah red-carded late on, pulled a goal back through Nino just after half-time but they were already 3-0 down at the time.
Ronaldo's goals lifted him two clear of Barcelona's Lionel Messi at the top of the scoring charts, but the Argentina superstar reduced it back to one when he scored from the spot as his men beat Athletic Bilbao 2-0.
Andres Iniesta opened the scoring as Barca rarely had to leave second gear.
Malaga's bid for a Champions League spot suffered a blow as they slumped to a 2-0 home defeat to Andalusian rivals Real Betis.
Ruben Castro and Jose Dorado netted the goals in the final five minutes of the first half as Malaga, who could have moved three poitns clear in third place with a victory, suffered a rare defeat after winning five and drawing the other of their previous six matches.
At the other end of the table, Real Zaragoza continuted their impressive charge to escape relegation as they picked up their third successive victory and fourth in six matches - they only have seven all season - with a 2-1 win at Sporting Gijon.
After a nervy opening, Helder Postiga gave the visitors the lead but Sebastian Eguren equalised for Sporting three minutes into the second half.
However, Zaragoza would go onto claim the points thanks to a stoppage-time winner from Angel Lafita.
Guilherme Siqueira's 89th-minute penalty was enough to secure Granada a deserved 1-0 win over second-bottom Racing Santander.