Cristiano Ronaldo scored two goals and set up another to power Real Madrid's blistering attack to a 5-0 demolition of Valencia, while Atletico Madrid chipped into Barcelona's lead by maintaining its perfect record at home.
Madrid decided the match by half time with doubles by Ronaldo and Angel Di Maria after Gonzalo Higuain had opened the scoring.
Atletico eased to a 2-0 win over Levante, breathing an inkling of life into the title chase, but lost Colombian striker Radamel Falcao to a leg injury after he was forced off having pulled up from a sprint. Atletico coach Diego Simeone said Falcao is likely to be out for "around 20 days".
Atletico took advantage of Barcelona's first league defeat of the season - a 3-2 loss to Real Sociedad on Saturday - to reduce the gap to the pacesetters to eight points. Barça coach Tito Vilanova described the loss as a wake-up call that his side needed.
"It was inevitable we would eventually lose a game," Vilanova said. "It puts us in our place, there is still a long way to go in La Liga."