Madrid are looking to bounce back from last week's defeat at Osasuna.
"I'm sure it's going to be a nice match, but we are going to have to work hard to win the three points," the Spain international told Bwin.
"Sociedad made things very difficult for us in Anoeta and I'm sure they are also going to make thing difficult at the Bernabeu.
"They have good players in attack and especially on the wings.
"Xabi Prieto, (Raul) Tamudo, (Antoine) Griezmann are doing well, and (David) Zurutuza is also a quality player, and maybe the fact that they are coming here without any pressure will make them feel more comfortable.
"They are good up front, so we will have to be very focused."