Chelsea had been heavily linked with Higuaín, with new boss Sarri had got the best out of the 30-year-old striker at Napoli.
The Argentina international enjoyed the most prolific season of his career under Sarri, scoring a record-equalling 36 goals in the 2015/16 Serie A season.
As much as Sarri was keen for a reunion, though, the West London outfit did not do enough to sign the former Real Madrid hitman.
The Rossoneri made their move and ultimately secured a £16 million one-year loan deal, with defender Leonardo Bonucci heading the other way to Juventus in a deal that also involved Mattia Caldara moving to Milan.
Higuaín was unveiled to the media on Friday and he revealed why he ended up in San Siro and not Stamford Bridge.
The esteem I hold Sarri in isn't new.
However, the only person who wanted me there was him. Everyone wanted me here.
That's the best thing for a player, the motivation and belief to bring you here.