The Frenchman pointed to the fact that Los Blancos will need many players to step up if they are to knock out the Sky Blues, who have a 2-1 advantage from the first leg.
"Ramos is a very important player," Varane said.
"I talk a lot with my teammates and my way of playing will not change.
"We need many leaders, and this will not change.
"We know the importance of Sergio in this group and we are all going to have to have a great game."