Real travel to Racing on Sunday, with Holland international Van der Vaart stressing the magnitude of the clash ahead of facing Barcelona at the Bernabeu on April 10.
Van der Vaart hopes victory over Racing will see Real maintain their place atop the standings ahead of the Barca battle.
"Our next opponent is Racing, and that is the only team we have in mind right now," said Van der Vaart.
"It is an important match because it won't be easy playing them on their home turf. We can start talking about Barcelona if we beat them.
"We need to win a lot of matches if we want to win La Liga.
"Winning on Sunday is very important because we want to play against Barcelona as the top team in the table."