Raiola believes Asensio can be one of the world's next great players.
He remarked to El Mundo Deportivo: "Asensio is a phenomenon. Real Madrid has a craque for several years, his signature is a success.
"I've known him since he played as a youngster at Real Mallorca.
"I am very disappointed not to have signed because I was really close to him when he was in Majorca."