Ronaldo is currently flourishing for Juventus after choosing to quit Real Madrid during the summer transfer window.
The Portugal international has bagged nine goals to propel the Serie A giants to the top of the table.
Manchester United, AC Milan and Paris Saint-Germain were all backed to sign him but Juventus ended up winning the race for his signature.
And midfielder Zidane, the son of Real Madrid icon Zinedine Zidane, has admitted Ronaldo’s exit was shocking at the time.
“I did not expect it, no one expected it,” he said.
“He decided to leave and he is doing very well.
“The lack of him is felt, but Madrid remains a great club even without Cristiano.
“I do not doubt that the team will adapt and achieve great results.”
Real Madrid have missed Ronaldo’s sparkle since cutting the Portugal forward loose.
And, speaking recently, Andre Villas-Boas admitted the La Liga giants were wrong to sell their star performer.
“It totally surprised me,” he said when asked about Ronaldo.
“How do you sell Cristiano for 100 million? It does not make sense from any point of view: neither sport nor economic.
“Congratulations to Juventus for the blow they were able to make.”
Ronaldo is next in action against Fiorentina tonight (5pm).
Real Madrid, meanwhile, go up against Valencia (7.45pm).