La Viola were 2-0 down with 25 minutes left and also down to 10 men following an early red card for Nenad Tomovic.
Montella thinks that his team deserve credit for forcing their way back to earn a point against an in-form Milan side.
He told Sky Italia: "I think the mentality we are forming this season helped us to have belief and courage, even when 2-0 down in a decisive moment of the match.
"There was a great reaction and I saw a team that strongly believed in this comeback against a very talented side, even with 10 men."
Fiorentina are still six points behind Milan following the late fightback with 52 points from 31 Serie A games.