Roberto Mancini's men won the title on the final day with an injury-time winner over QPR but Ronaldo, who spent six years at Old Trafford winning three Premier League titles, does not think the champions will retain their crown.
"It is the most competitive league in the world, in my opinion ahead of Spain. You have a lot of brilliant players and the league is so intense it's amazing. I watch it in my house every week," he told the Daily Mail.
"I think United will do it this year and win their trophy back."
|EYES ON THE PRIZE?
|4/1||Cristiano Ronaldo is 4/1 to win the 2012 Ballon d'Or with William Hill|
During his time back in England, the Portuguese captain met up with former manager Sir Alex Ferguson but he insisted a move back to Old Trafford was not discussed.
"We didn't speak about that [returning to United]. We just spoke about his moment with Manchester United and mine with Real Madrid. We were just happy to see each other," he added.
"I have enjoyed coming back to Manchester. When we arrived at the airport I was so happy. I had a beautiful story here in Manchester so it was nice to see all the fans and a few Manchester United shirts, too - I am always happy to be here."