Ronaldo fired a hat-trick as Madrid saw off their city rivals at the Vicente Calderon in November, part of a 26-goal haul in all competitions for the four-time Ballon d'Or winner this season.
The 32-year-old was rested for Wednesday's 4-2 win at Leganes and is set to take centre stage once more, having scored 18 times in 26 previous derby appearances.
"He knows, as we all do, but even more so Cristiano, that in the big games he is always there," Zidane told a pre-match news conference.
"I don't know if it is because he's accustomed to it, but his ambition makes him want to play well in the big games like every player.
"That's what he trains for, he's been training very well. He's ready for the final stretch of the season.
"But not just the big games, any game he plays in he wants to score and be a big player for his team.
"It's very positive for everyone, the energy that he generates."
The sight of Ronaldo sitting out Madrid games to preserve him for the season's major battles has become familiar under Zidane and he maintains his star player is on board with the policy.
"There's no special plan. We just speak to Cristiano and that's it, like we do with all of them," he said.
"I speak to all the players about what we're going to do. It's important that the players understand what we're doing.
"They're intelligent players, they know my idea and we're all together."
"The idea is to get to the end of the season in the best possible physical shape.
"I think when Cristiano or Gareth [Bale] don't play we know it's because there are a lot of games coming up and the other players who are training, I know what they can bring to the team.
"Every game is a story in itself. We know that. That's why we go game by game. Hopefully we are going to end the season very well."
Madrid retaining their two-point advantage over Barcelona at the top of LaLiga as they head into the season's pivotal closing stretch owed much to Alvaro Morata's hat-trick at Leganes.
Morata has outscored Karim Benzema in the league and, with a growing clamour for the Madrid-born striker to be handed his chance in a major contest, Zidane took a diplomatic route.
Asked where it was time for the Spain international to start a big game, he said: "Every game is important, the other day in Leganes was an important game and Alvaro played very well.
"So I'm not sure what you mean but we're going to keep going like this with all the different players."