Dida insists the France goalkeeper will prove himself the best in the world.
He told Il Gazzetta dello Sport: "I have no doubts about Mike because I trained him and I am convinced that he will become the best in the world. He is very strong between the posts and (Paulo) Fonseca's game, which involves him even more, will enhance his skill with his feet.
"Renewal? He must stay by force. We cannot lose him!"
Dida also spoke of the new Rossoneri cycle under Fonseca:
"The team is assimilating his game and it seems to me that the players are going to attack the opponents higher up. Fonseca's work is visible. The challenge against Atalanta? It will be important to confirm that the team is growing. I continue to support Milan to go far. It will be tough against Atalanta, but I am confident."
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