The Portugal captain angered some Madrid fans by celebrating his 30th birthday on Saturday night, just hours after putting in a below-par display in the 4-0 derby defeat to Atletico Madrid.
But Ancelotti says there are few players who can match the level of the Ballon d’Or winner and hailed his influence in the dressing room.
“I should write a book, or at least, a long chapter on him,” Ancelotti told Portuguese sports newspaper A Bola. “Cristiano is a player with an efficiency that is unique in today’s football.
“He has an extraordinary talent and he enjoys it with such a professionalism and seriousness that is difficult to find in a player of that level.
“In the (Real Madrid) changing room he is the leader. He speaks a lot to his team-mates, especially to the young ones. He is a very important figure, just like Pepe, Sergio Ramos, Iker Casillas or Marcelo.
“If he continues to feel the passion that he has for what he does, he can continue until who knows when, thanks to his great physique and unique genetics.”
Despite not enjoying the best start to the year, Ronaldo has still had a remarkable season, scoring 28 goals and providing nine assists in just 19 league appearances.
When asked if Ronaldo can win another Ballon d’Or, Ancelotti said: “Of course. Without a doubt!
“He plays in a great team which he will help win more trophies and that, in turn, will contribute to him continuing to be the best in the world.”
Since joining the Bernabeu outfit from Manchester United in the summer of 2009, Ronaldo has helped Madrid win one La Liga title, one Champions League, a European Super Cup and lifted two Copa del Rey trophies.
Ronaldo and Madrid wrapped up a wonderful 2014 in December by clinching a FIFA Club World Cup crown, their fourth title that year.
The Merengue outfit currently lead the Primera Division standings, one point clear of Barcelona.
Ancelotti’s side is also alive in the Champions League and take on Schalke 04 in the last 16 of the competition next week.