United will face rivals City in the Premier League on Sunday.
“I have been very impressed with Robinho,” said the Scotland international.
“He is a world-class player who has scored some fantastic goals. But he has not come as a prima-donna with a big superstar attitude.
“He has knuckled down, worked hard and done his best for Manchester City, which you have to respect.
“I have also seen a few hard challenges going in on him. But similar to Ronaldo here, he just picks himself up and gets on with it.”
