Madrid can still end 2011 ahead of Barcelona, who are currently in Japan competing in the FIFA Club World Cup, if they win their game in hand.
Perez said: "If we win at Sevilla on Saturday, we will see the future with more hope. To lose against Barca will be secondary if we go to the Christmas break with a three-point advantage and the feeling of having recovered the form that allowed us to get to the top.
"We must forget Barca until April. In the last 17 games we have won 16. Where is the crisis?"