Barca boss Tito Vilanova claimed that Messi is the best player in the world by a 'big margin', but Mourinho believes that Ronaldo is better, and claimed that it would be a "crime" if he didn't win the Ballon d'Or this year.
"When someone with the same responsibility as me comes out and says 'Mine is the best on the planet' then I have to say mine was not born in Madeira, he was born on Mars; he is not from planet Earth, he is the best in the universe," Mourinho told A Bola.
"If Messi is the best on the planet, Ronaldo is the best in the universe. It would be a crime if Ronaldo did not win the Ballon d'Or."
Ronaldo has scored 14 goals in 11 games for Madrid so far this season, bringing his overall tally for the club to 160 goals in 155 matches.