Real Madrid saw its rivals falter and then did its part against Real Sociedad, winning 3-0 with a goal and an assist by Cristiano Ronaldo to increase its lead in the Spanish league.
Madrid opened a four-point gap on Barcelona and Sevilla, which failed to win their matches earlier Sunday.
Second-placed Barcelona needed a late equaliser by luis Suarez to draw at Real Betis 1-1, while 10-man Sevilla lost 3-1 at Espanyol.
Fourth-placed Atletico Madrid was held to a scoreless draw at promoted Alaves on Saturday, staying 10 points off the lead.
Madrid's advantage could become even bigger as it has a game in hand at Valencia.
"We are not thinking about what the other teams are doing," Madrid midfielder Casemiro said.
"We have to do our part and keep winning."
Ronaldo set up Mateo Kovacic's opening goal with a clever through ball in the 38th minute, then scored himself with a neat chip shot over the charging goalkeeper in the 51st.
Alvaro Morata netted the third with a diving header in the 82nd, only 10 minutes after he had a goal disallowed for offside.
Ronaldo, who was jeered by some fans early in the match at Santiago Bernabeu stadium, also had a goal disallowed for offside in the 90th.
Real Sociedad played a man down from the 74th as Inigo Martinez was shown a second yellow card for a hard foul on Casemiro.
It was the fourth win in the last five league games for Madrid, which was coming off elimination against Celta Vigo in the Copa del Rey quarterfinals.
ESPANYOl 3-1 SEVIllA
Sevilla could have provisionally moved into first place had it won earlier at Espanyol, but it had to play nearly the entire game with a man down as Nicolas Pareja was sent off in the second minute after conceding a penalty.
Jose Antonio Reyes converted the penalty to put the hosts ahead, and Gerard Moreno and Marc Navarro added goals for Espanyol after Sevilla equalised through Stevan Jovetic.
"The red card that early changed the game completely," Sevilla defender Sergio Escudero said.
The result snapped Sevilla's five-game winning streak in the league.
It was Espanyol's second consecutive victory, leaving the club from Barcelona in ninth place.
BIlBAO 2-1 SPORTING GIJON
Seventh-placed Athletic halted a three-game winless streak with a come-from-behind victory over relegation-wary Sporting Gijon.
Veteran striker Aritz Aduriz scored the winner by converting a penalty kick in the 71st minute at San Mames Stadium.