Ronaldo fired home a treble as Real thumped Girona 6-3.
Zidane stated: "It is very important for us to transmit important and positive energy for the rest of the group, he knows himself and knows when he has to stop a little and at the end of the season he is always in very good shape.
"The goals? He's always going to get them."
He also said: "What he has is ambition, he's tremendous in every practice in every play ... if he has to shoot a penalty in training he does it with maximum concentration, that makes him different, others help him a lot, we made spectacular goals and it's everybody's, the players."
Zidane added: "He comes from another galaxy, it's true, it's good for us and for him, when he's fine, the team is good, he transmits a very good energy."