Carlo Ancelotti's side will enter the contest off the back of a 5-0 win over Shakhtar Donetsk in the Champions League on Tuesday night.
However, Real Madrid have not been in league action since a 2-1 loss to Espanyol on October 3, and Valverde has insisted that his team must be "united" in order to overcome their bitter rivals.
"I'm a bit nervous, but also excited and really proud to be able to play in these types of games," Valverde told Real Madrid TV.
"We [the Real Madrid players] are highly motivated to win this game. We have to be united, I think that's crucial. Whoever plays, whether it's from the start or later on, has to be ready for the demands of the coaching staff.
"That's essential for everyone. Everyone has to chip in with their part here. I think it's going to be a great season for us if we can do that."
Real Madrid are currently third in Spain's top flight, having picked up 17 points from their opening eight matches of the 2021-22 campaign.