The Liga leaders triumphed 2-1 at the Santiago Bernabeu to move four points clear of Barcelona at the top of the table but the victory came at a cost, with James Rodriguez, who opened the scoring, ruled out for two months with a foot fracture, and Sergio Ramos suffering a suspected hamstring tear.
In addition, Marcelo picked up a booking that means he will miss the derby through suspension, meaning Madrid will be particularly short on numbers at the back, with Pepe already having been ruled out of the trip to the Vicente Calderon through injury.
Ancelotti, though, is looking on the bright side, buoyed by the fact that Los Blancos will be buoyed by the return of their top goalscorer, who missed their last two games on account of his red card in last month's victory at Cordoba.
"Cristiano Ronaldo's comeback is important for us," he told reporters. "It's very good news.
"We won two games without him, but he's certainly going to help us against Atletico."
Ancelotti added that Madrid have not given up hope on having Marcelo available for the derby, but he insists that no matter what happens, the reigning European champions have sufficient strength in depth to defeat their city rivals.
"We will appeal Marcelo's yellow because it was not a foul on Vitolo but Fabio Coentrao trained this morning and is available for the derby," the Italian coach said.
"We'll have less experience without Pepe and Sergio Ramos, but we'll have the enthusiasm of Nacho and Raphael Varane."
The Italian has also been lifted by the performance of Jese, who scored Madrid's second goal after coming on as a replacement for the injured James.
"We have seen the Jese Rodriguez we saw last year," the former Chelsea boss said. "He has worked very hard to recover from last year's injury and his performance today was very good.
"He was important in attack, helped in defence and scored. A complete game."
