Real Madrid lead Real Sociedad 1-0 at half time at Estadio Anoeta courtesy of Asier Illarramendi's 45th-minute goal.
The first opening of the contest fell to Carlos Vela, who connected well with a close-range header, but he was denied by Sergio Ramos, who blocked the effort which was heading towards goal.
The hosts had another opportunity to score the game's opening goal, this time Vela turning provider for Antoine Griezmann, who flicked his teammate's cross towards the far corner, with the effort sailing narrowly over.
Madrid were unable to create any real openings and the first half looked to be edging towards a stalemate, but Illarramendi managed to find a breakthrough, tapping in a rebound after Claudio Bravo had failed to clear Karim Benzema's powerful strike.
