Schuster accepts it will be almost impossible to prise the Portugal winger away from Old Trafford in the near future but reckons he will one day join the Spanish giants.

"In these types of things it is best to be realistic. Cristiano Ronaldo right now is a 10 out of 10, the best in the world," said Schuster of the player who last night scored his 36th goal of a sensational season.

"But I don't see Manchester United as being in the business of selling."

Schuster added in Spanish newspaper AS: "In the short term I cannot see it as being possible, but I think in a few years that he could wear the Madrid shirt in the Bernabeu.

"He is the star at Old Trafford and until he wins a Champions League and some more Premier League titles they are not going to allow him to escape."

Comparing 23-year-old Ronaldo with the reigning World Player of the Year, Schuster said: "For me, Cristiano Ronaldo is already better than Kaka after the Brazilian's loss of form at Milan this season.

"Some day he will be with us..."

Schuster also spoke highly of Chelsea striker Drogba and Sevilla's Luis Fabiano, the leading scorer in Spain'sPrimera Liga this season.

"For me they also seem very good," Schuster said. "Madrid, if they sign, have to aspire to get the best."