Valencia's new manager, Juan Antonio Pizzi, debuted with a 2-0 victory at home over crosstown rival Levante, while Real Betis remained bottom of the table after a drab 0-0 draw at Valladolid.
Pizzi replaced the fired Miroslav Djukic over the two-week league break, and Valencia responded with a convincing win in the city derby against Levante at its Mestalla Stadium.
After Pablo Piatti drilled in a clearance to put Valencia in front three minutes before halftime, forward Sofiane Feghouli dribbled through the defense and chipped the ball home via the crossbar in the 73rd to put the result beyond doubt.
Betis' draw at Valladolid gave the Seville-based side its second point away from home this season.
Elsewhere, Atletico Madrid needed a second-half goal from midfielder Jorge "Koke" Resurreccion to eke out a 1-0 win at Malaga on Saturday, becoming the overnight leader of the Spanish league as it resumed following the winter break.
Atletico built a provisional three-point advantage over Barcelona before the defending champion hosts Elche on Sunday. Barcelona then visits Atletico in the following round.
"We will have to wait and see if Barcelona wins tomorrow to stay leader, as it is accustomed to doing," Atletico coach Diego Simeone said.
Atletico dominated possession but was held in check by Malaga's five-man defense until Simeone sent on forwards Adrian Lopez and Cristian Rodriguez to join Diego Costa and David Villa up front for the final half hour.
Diego Costa failed to add to his league-leading 19 goals, but the striker turned playmaker to unlock the hosts' stingy defense in the 70th.
Diego Costa slipped the ball to Adrian, whose rebound off goalkeeper Willy Caballero fell for Koke arriving late to rifle through the crowded area and into the back of the net to claim the winner.
"They played a great game in defense but eventually we earned the victory with my goal. That is important for us to take three points back home," Koke said. "The team believes in what it is doing."
Atletico moved eight points clear of third-place Real Madrid before it hosts Celta Vigo on Monday.
Atletico continued to base its title challenge on Spain's best defense, which again left its opponent without a clear scoring opportunity. It has conceded a competition-low 11 goals through 18 games.
The loss was the first in four rounds for Bernd Schuster's Malaga, leaving it in the middle of the standings.
Schuster defended his strategy of trying to stop Atletico by playing with three central defenders, which arguably hurt its efforts in attack.
"If somebody believes they can play Atletico as equals with what we have, then go ahead, I'll pay them to do it," Schuster said. "They are better than we are and didn't need a great game to beat us."
Granada visited Almeria later.
Also on Sunday, it's: Real Sociedad vs. Athletic Bilbao, Sevilla vs. Getafe, and Osasuna vs. Espanyol. Villarreal plays at Rayo Vallecano also on Monday.
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