The pair played together at AS Monaco.
Kurzawa said at a Nike event: "Like that no, it has happened very quickly for him. It's true. But this is a player who has a lot of potential and talent.
"I knew that sooner or later he was going to explode. He has a lot more than others. For him, what's happened is a dream."
He added: "His move to Manchester United was sudden, but if it was not this year it would have been next year."
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