Real Madrid established a two-point lead over Barcelona in the La Liga title race by beating Espanyol on Sunday night, thanks to Casemiro's composed finish.
Los Blancos were largely dominant in terms of possession and shots taken but left it until the 45th minute to take the lead, with midfielder Casemiro latching onto Karim Benzema's brilliant backheel to fire the visitors in front.
Real were previously only ahead of Barcelona by virtue of their better head to head record, but La Blaugrana's slip up on Saturday at Celta Vigo handed the Madrid side the chance to turn their lead into a more solid one.
The victory was Real's 104th against Espanyol - they are the only club to have beaten a team 100 times in Spain's top flight. The result means the Catalonian side remain rooted at the bottom of La Liga, ten points adrift of 17th-placed Celta Vigo with just six games remaining.
Zinedine Zidane made changes from the starting XI that beat Mallorca 2-0 in his side's last outing, with Casemiro returning in midfield, while Gareth Bale dropped to the bench. Karim Benzema was joined up front by Eden Hazard and Isco on the flanks.
Espanyol went close to opening the scoring early on as Raul de Tomas saw his effort blocked, before Casemiro took a shot from his own half, causing Diego Lopez to scamper back towards his own goal to keep it out.
The win means Real's perfect post-lockdown record remains in tact, having previously beaten Eibar, Valencia, Real Sociedad and Mallorca.
Real are next in action on Thursday, when they host Getafe. They'll be watching on keenly on Tuesday, however, hoping their city rivals Atletico can puncture Barça's title charge at Wanda Metropolitano.