Kaka surprised by Ronaldo move
The Brazilian completed his switch from AC Milan for a fee of around £56million last Monday.
Only three days later, Manchester United confirmed they had accepted a bid of £80million for Ronaldo from Madrid, although the Portugal international has not completed the move.
"I was quite surprised because everything was sorted so quickly," Kaka said.
"It was pleasant surprise, not a bad one. He is an excellent player who can bring a lot to the team.
"To have players who can decide a match on their own is very important and Cristiano can do that," he said.
Asssuming Ronaldo's deal is completed, the double capture of the Portuguese talent and Kaka represents a stunning raid to land perhaps the best two players in world football.
The amount of money being spent by Madrid under president Florentino Perez, who returned this summer for a second spell in charge, has come in for strong criticism, but Kaka defended the architect of the 'Galacticos' policy.
"It is a political problem," Kaka said. "Florentino has his project, his way to invest. It is not something negative for football, but positive.
"The Barcelona president [Joan Laporta] has criticised us, but they are very strong," he said.
"The way Real can be a competitive team again is to have an ambitious project like Florentino's."