Ronaldo, speaking at a promotional event in Madrid, said: “He (Falcao) is very good player. I think Manchester did very well. I don’t think he is the wrong type of player. He is a top player so I don’t think it is a wrong buy.
“I think he will be a fantastic buy. Manchester have not started well, two points, so they need quality players and Falcao is a quality player.”
However, Ronaldo went on to critique Real Madrid’s summer spending saying the club's transfer policy would probably be different if he was in charge.
After winning a record-extending 10th European Cup crown last season, when dressing-room heavyweight Ronaldo was the team's top scorer, Real sold midfielders Xabi Alonso and Angel Di Maria and brought in Toni Kroos and James Rodriguez.
The departure of Alonso to Bayern Munich, in particular, has raised questions about whether the Madrid club will have enough quality and experience in midfield without him.
Alarm bells rang when they let slip a two-goal lead to crash to a 4-2 defeat at Real Sociedad in La Liga on Sunday, with Ronaldo sidelined by injury.
"I have a very clear opinion but I cannot always say what I think," the Portugal forward told reporters at a promotional event in Jerez when asked about his club's recent transfer dealings.
"If not I would be on the front page of the newspaper tomorrow and I don't want that. But, if I was in charge, maybe I would not have done it like that.
"But if the president thinks that the best thing for the team is to buy the players he bought and let others leave we have to respect and support his decisions."
Ronaldo's comments will make uncomfortable reading for construction magnate Perez who has spent hundreds of millions of euros on top players and turned Real into the world's richest club by income.
"With the new players the style will change but it could change for the better or for the worse," added the World Footballer of the Year.
"Hopefully it will be for the better because they are players of a very good level. It would be normal for them to adapt well.
"Di Maria and Xabi were very important for us but they are not here any more and we have to be happy with the new ones. I am sure that it will go well for us," said Ronaldo.
- Sports & Recreation
- Xabi Alonso
- Angel Di Maria