Barcelona turned in another superb performance to demolish Getafe, while Atletico Madrid were beaten by Rayo Vallecano and there were away wins for Real Sociedad and Espanyol.
Having been held to a 1-1 draw by Valencia last weekend, Barcelona bounced back to crush Getafe 6-1 in the day's early kick-off and strengthen their position at the top of the table.
Alexis Sanchez opened the scoring with his first goal of the season after less than six minutes and Lionel Messi celebrated putting pen to paper on his two-year contract extension earlier this week by notching - for the 13th straight game in La Liga - on 13 minutes.
David Villa's neat finish made it 3-0 in the 57th minute and substitute Cristian Tello added another 11 minutes from time.
Getafe substitute Alvaro Vazquez then grabbed a consolation for the visitors but there was still time for Andres Iniesta and Gerard Pique to add further gloss to the scoreline for the hosts.
First-half strikes from Alhassane Bangouraan and Leo Baptistao saw Rayo Vallecano to a 2-1 victory in the Madrid derby over Atletico.
Second-placed Atletico - who had lost just one of their last 10 - were never in the game with Radamel Falcao's last-gasp strike a mere consolation, while defensively their inability to stop and defend crosses into the box was their downfall.
The result means Atletico now trail Barcelona by 12 points and are just four clear of third-placed Real Madrid.
Real Sociedad boosted their push for a Europa League place as goals from Antoine Griezmann and Imanol Agirretxe saw off Real Zaragoza 2-1.
Zaragoza left-back Hector endured a nightmare league debut, sent off for two bookable offences after only 22 minutes to deal his team, already a goal down, a blow from which they would not recover.
Griezmann had opened the scoring after 11 minutes and Agirretxe doubled it shortly after the hour mark, with Zaragoza made to wait until deep in injury time for Apono to get their goal from the penalty spot.
Espanyol climbed above Athletic Bilbao as they capitalised on a miserable day for the Basque side with a 4-0 win.
Athletic had plenty of chances and possession but no luck and Espanyol took full advantage with goals from Hector Moreno, Victor Sanchez, Christian Stuani and Joan Verdu.
