Ronaldo penned new terms to 2021 on Monday.
“Spanish football is fortunate and privileged that Ronaldo is here and that we can enjoy a player of his class,” said Real Madrid chief Emilio Butragueno.
“Probably after di Stefano he is the most important player in Real Madrid history.”
Ronaldo has declared that he expects to play on for a further 10 years, taking him into his 40s.
“He’ll only play until he’s 41 if he continues to offer this level of performance,” Butragueno added.
“At least until 2021, he’ll be here. But we’d like to have him for many more years.”