Real Madrid have a two-point lead at the top of the La Liga after beating the Espanyol club.
Casemiro scored the only goal by clinging to Karim Benzema’s shiny rear wheel between the legs of defender Bernardo Espinosa before shooting home.
The Brazilian had previously approached the opening of the score when his own half’s shot had been saved by Diego Lopez.
Espanyol had several opportunities with Thibaut Courtois making five saves.
Sports director Francisco Rufete took office as manager on Saturday after replacing Abelardo Fernandez – the third Espanyol boss to be sacked this season.
They fought well, with Wu Lei among the players to approach, but failed.
Real Madrid are just six wins – or five wins and one draw – from a second Liga title since 2012.
The city’s rivals Atletico can do them a favor when they visit Barça on Thursday.