The midfielder shone in victory over Cagliari on Sunday.
Montella stated: “If I have to single out any player I will do it to Montolivo. I have seen him grow a lot.
“After an injury of that type it needs time. Today he played well."
The Milan boss refused to comment on M'Baye Niang's future at the club.
“Niang? I can't comment on that every time."