The former Liverpool and Valencia boss signed a three-year deal to replace the sacked Carlo Ancelotti after agreeing to end his spell with Napoli.
And Zidane, who currently coaches the Madrid Castilla side, says Benitez is well aware that he must deliver trophies if he is to survive at the Santiago Bernabeu.
"The club has selected Benitez and it's a good decision," he was quoted as saying by Marca. "You need to respect that decision. Benitez is a good choice, but what counts are results. He knows the place well. He knows the challenge he has ahead. Only winning titles is good enough."
Zidane, who was himself reported to be in the running for the head coach role, says he is happy to continue progressing with the Castilla side.
"I want to keep learning," said the former France star. "Then I'd like to manage in the top division. I'll progress bit by bit, as I did as a footballer. We'll see if it's here or somewhere else.
"I'm staying with Castilla because I want to carry on. We had a target and we didn't achieve it. I want to achieve it. It's been a good experience. It's a completely different job from working with the first team. We're looking to get promoted. I decided to stay because Real Madrid is an amazing place and I want to contribute something important to this club".
Zidane also defended club captain Iker Casillas and has no doubt the Madrid fans will give him the same sort of send-off as Xavi has enjoyed at Barcelona in future.
"Iker is still active and when he leaves Real Madrid he'll be honoured in the same way as Xavi was," he said.
Finally, the 42-year-old offered words of support for Ancelotti.
"The president didn't speak with me about it when he took the decision [to sack him]," he explained. "I like Ancelotti and that's why I spoke with him. He did an impressive job with Real Madrid, winning many titles. It was the club's decision."
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