Ronaldo said: "Manchester United is the favourite. Milan, Barcelona, Real Madrid and Inter also have good chances. We want to reach the final at the very least.
"I am extremely ambitious and want to win every title."
The Portuguese wideman also revealed his ambitions for his national team.
He said: "I especially want to win the World Cup.
"For Portugal to get fourth place in Germany last year was not a failure."
And Ronaldo has backed England to go close at Euro 2008 next year.
He said "Germany, France, Italy, England and Portugal are the Euro 2008 favourites."