Reigning champions Barcelona were surprisingly beaten at Real Valladolid on Saturday, and Carlo Ancelotti's side took advantage 24 hours later with a routine victory at the Bernabeu.
Cristiano Ronaldo headed Madrid's opener and then laid on an assist for Marcelo's first league goal of the season.
David Navarro was sent off for a late tackle on Ronaldo before Nikolaos Karabelas put the ball into his own net as the hosts eased to a 16th straight home win in all competitions.
Real's nearest challengers in La Liga are city rivals Atletico, with Barca now four points off the pace in third.
Fourth-placed Athletic Bilbao came from behind on Sunday to claim a 1-1 draw against Valencia.
Ander Herrera struck the post for Bilbao before Valencia moved ahead in the 23rd minute through Paco Alcacer.
The goal was set up by Sofiane Feghouli, who then turned from hero to villain when conceding a 53rd-minute penalty that Aritz Aduriz converted.
Sevilla proved too strong for Almeria, who occupy 18th position following a 3-1 home defeat.
Goals from Carlos Bacca, Daniel Carrico and Kevin Gameiro earned a third successive victory for Sevilla, who sit seventh.
Aleix Vidal pulled one back late on, but the goal provided little consolation to an Almeria outfit winless in four.
In Sunday's other fixture, Espanyol recorded a 3-1 home triumph over another struggling side, Elche.
Fran Escriba's men were given a mountain to climb when David Lopez and Diego Colotto found the net inside the first 21 minutes.
Pizzi popped up with a third before the hour mark, ensuring Juan Fuentes' late own goal was of little significance.
