That's according to Atalanta president Antonio Percassi, who detailed the teenager's stunning switch to Old Trafford.
He told L'Eco di Bergamo: "The negotiation with Manchester lasted almost a year.
"The details and the scenarios are crazy. Meeting after meeting we learned unimaginable things.
"This leads to the growth of the club and enriches the work of everyone, from the general manager, Umberto Marino, to the entire staff."