The Rossoneri will head into the match on the back of two-straight Serie A defeats, while Inter are yet to lose in the league this term, winning six of their seven matches to date.
Argentina international Icardi has been Inter's star performer during the opening weeks of the season, netting six goals in seven league appearances, and Musacchio knows AC will have to be on their guard against his compatriot, although he is also wary of Inter's other threats.
“Icardi? We can’t let him breathe, but not just him," Musacchio said. "They have a good team, so we have to stay focused on all their players if we want to be happy at the end of the game.
“We need to be 11 lions, we’ll put everything out there on the pitch. And, of course, we’ll need the support of our fans too."
Sunday's match at the San Siro will be Musacchio's first Milan derby, following his arrival at AC from Villarreal during the off-season, and he admits he is relishing the prospect of playing in such an emotionally charged game.
He added: “It’s very emotional and exciting and there’s a huge desire to win. I look forward to Sunday.”