Real Madrid will meet Bayern Munich in the semi-finals while Barcelona have been drawn against English club Chelsea for a spot in the final at Bayern's Allianz Arena May 19.
The three-time FIFA world player of the year believes the Spanish clubs are in a class of their own despite Bayern Munich's recent impressive form.
"Real Madrid and Bayern Munich are both playing at a high level and it will be a hard-fought semi-final, but I believe Real will go through," Ronaldo was quoted as saying by Xinhua.
The 35-year-old scored 47 goals in 49 games in his only season with the Catalan club and 104 from 107 appearances with Real Madrid.
The member of Brazil's 1994 and 2002 World Cup winning squads also believes Real coach Jose Mourinho will continue being the manager at the Bernabeu next season.
"He has a winning mentality and tremendous ability to forward that on to the players," Ronaldo said.
"He has a great team capable of winning everything. I think he will stay at Real. I don't think he will leave until he achieves all of his goals."
Ronaldo's Champions League prediction is not shared by Argentine idol Diego Maradona.
After watching Bayern's clinical 4-0 aggregate victory over Marseille in the quarterfinals, Maradona tweeted: "I'm telling you now, Bayern will eliminate Real Madrid. There will be no all-Spanish final."
Source : Afghan Voice Agency (AVA), International Service