The Italian champions lock horns with their Spanish counterparts in Wednesday's Champions League Group H game and Seedorf is looking forward to seeing Messi in action.
"Lionel Messi is the best player in the world. He plays at a very high level and he is a joy to watch for everybody," Seedorf said to Cope.
"However, Cristiano Ronaldo is not far behind him. He has already done a lot for Real Madrid and is very important."
The Dutchman then went on to stress that Milan are not one of the favourites to win the Champions League as he feels other teams are sitting in pole position to lift Europe's top club prize this season.
"It's clear that we are not the favourites. I'd say that Barcelona, Real Madrid and Manchester United are the main candidates to win the Champions League."
Wednesday's game at San Siro kicks off at 19.45GMT.
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