Los Blancos will attempt to win a third straight European crown when they take on Liverpool in Kiev on Saturday night.
Ronaldo has insisted that the Reds "deserve respect", but the Portuguese would rather be taking on his former club United in the final of the competition.
"Finals are always special occasions - I would have preferred it to be Manchester United. But Liverpool deserve respect. We're not going to have it easy," AS quotes Ronaldo as saying.
"They deserve to be in the final. They remind me of Madrid three or four years ago. Their three front players, they're very quick... they are powerful in attack and I respect them. But Madrid are better. We have to play to our level, but we also have to respect the opposition."
Ronaldo has scored 15 times in 12 Champions League appearances for Madrid this season.