Real Madrid coach Jose Mourinho says he's unsurprised by Robin van Persie's success at Manchester United.

Mou says they must be wary of Van Persie in tonight's Champions League clash.

Mourinho said: "I am not surprised at all how well he is doing.

"It was easy for him to go from Arsenal to United.

"Same country, same culture, same language.

"He is in his natural habitat, a fish in water and at a club that wins trophies."