The Portuguese winger, who picked up a FIFA trophy on Monday night for coming third in their world player of the year award, also believes it is a mistake to view the title race as a two-horse contest between United and Arsenal.
Wins for United and Arsenal on Sunday over Liverpool and Chelsea respectively means the top two now have a small but potentially significant gap in the league table.
Ronaldo said: “Arsenal play fantastic football but I think we have a better team this season that we had last year.
“We have a good chance, we are at the top of the league, Arsenal and ourselves, but I don’t think it is just between the two teams.
“Chelsea and Liverpool are still there and are strong.
“I think we can challenge for the Champions League as well – we are through to the next round and I am looking forward to it.”
AC Milan’s Brazilian midfielder Kaka won the award with Barcelona’s Argentina forward Lionel Messi second ahead of Ronaldo.
The FIFA award is voted on by all national team managers and captains, and England skipper John Terry did not vote for Ronaldo or Kaka.
The register of votes shows Terry instead chose two of his Chelsea team-mates, Didier Drogba and Petr Cech, among his three choices as well as Messi.
Former England manager Steve McClaren chose Kaka, Ronaldo and Italy’s Gennaro Gattuso.
Kaka, Messi and Ronaldo are aged 25, 20 and 22 respectively and Brazil legend Pele believes a new generation of stars is now coming forward to steal the limelight from the likes of Ronaldinho and Thierry Henry.
Pele said: “That’s a good thing because life is like that. I was a new player when I started aged 17 and people like Didi, Newton Santos and Puskas were the old ones.
“I’m very happy because Brazilians won both awards – Kaka the men’s and Marta the women’s.”