Barcelona's 27-game unbeaten streak ended Saturday when the three-time defending La Liga champion lost, 1-0, to Getafe, whose Juan Valera scored in the 67th minute with a header off a corner kick.
Real Madrid opened a six-point lead over Barcelona thanks to a 4-1 comeback win over Atletico Madrid in which Cristiano Ronaldo converted two penalty kicks to take his season's tally to 19.
"The thing that pleased me most was our discipline," said Mourinho, who had unleashed his fury on the Atletico dugout in a stormy first half. "The reaction to our opponents. The players were kicked but they stayed calm. My men didn't want to play an ugly or rough game. Luckily they have carbon-fiber shinpads that work really well."
Real Madrid and Barcelona meet in the season's first El Clasico on Dec 10.