The France legend has hailed the forward's continued success with the Spanish giants and tipped him to star for Portugal in Brazil next month
The forward is expected to be fit for next weekend’s Champions League final against Atletico Madrid despite dropping out of the warm-up against Espanyol with a hamstring injury concern on Saturday.
Zidane has paid tribute to Madrid’s star man and is confident he will impress at the World Cup as Portugal prepare to do battle with Germany in the group stage.
"Ronaldo is an exciting talent. We see him train every day at Real Madrid and believe me, he is simply a genius," Zidane told The Times of India.
"I don’t see why he cannot carry his club form into the World Cup. What he has been achieving for Real Madrid is amazing.
"He is the best according to us, and I have every reason to believe that Cristiano will set the grass on fire.
"Yes, Portugal are in a difficult group with Germany but Cristiano has already shown his talents when they faced Germany at the same stage of Euro 2012.
"He is on song and when a footballer of his talent is on song, it is almost impossible to stop him.”
After again stating that Madrid believe he is the world’s best player, Zidane was inevitably asked whether Ronaldo had moved ahead of his Barcelona rival, Lionel Messi.
The Argentine is also aiming to secure a career-defining victory in Brazil this summer and the France legend admitted the Camp Nou star is a special talent.
Zidane continued: "This is difficult for us to say anything since we represent Real Madrid.
"But I must say Leo Messi too is a special talent to watch. Both of them belong to a special category and can win games on their own. As a football fan, we love to see both at their best."
Madrid defeated Espanyol 3-1 without Ronaldo as Alvaro Morata netted a double and Gareth Bale also found the target ahead of next week’s showdown in Lisbon.