Ronaldo, however, insists City will never take away United's crown as "king of England".
"I saw a few days ago (City scored) two goals in the last minute, 91 and 93. I had a bet that Manchester United would win the league but I lost," he said.
"I feel very disappointed because United is still in my heart.
"City have a fantastic team now, but I think Manchester (United) will carry on being king of England in my opinion."