The Arsenal manager also claimed United’s stars receive preferential treatment from referees.
Wenger spoke out after Ronaldo was involved in a furious tunnel bust-up with Newcastle’s Steven Taylor on Wednesday.
He said: “Every bad tackle that is unpunished is not right but with Manchester United I am a bit cautious because sometimes I feel they get too much protection.
“Ronaldo is a specific example of that. Sometimes his arrogance is provocative — and his class as well.”
Wenger reckons even if United win everything this season, it will not beat Arsenal’s 2004 Invincibles.
He said: “To win five trophies would be something very special, but I don’t think it is a bigger achievement than going through a whole season unbeaten.
“It is not impossible for them to win five trophies but I don’t think they will because the schedule at the end of the season is so tight.”
Toon defender Taylor escaped a red card when he caught Ronaldo round the neck with his arm during United’s 2-1 win.
Boss Alex Ferguson said: “Ronaldo is an easy target for referees. It is easy to give decisions against him because he is such a great player and he is so celebrated.
“When he is away from home every crowd boos him, so he has to handle that. But it is not helping him.”
it's true