Stefano Pioli is confident his Milan side will learn from a "painful" loss to Fiorentina after their unbeaten start to the Serie A campaign came to an end at Stadio Artemio Franchi.
Milan fell to a 4-3 defeat in Saturday's thrilling contest as they missed out on the chance to move three points clear of Napoli, who play their game in hand at Inter on Sunday.
The Rossoneri last tasted defeat in the top flight 18 games ago against Lazio in April, while not since August 2015 had they lost away to Fiorentina in the league.
Pioli's side were without a number of players through injury, including Fikayo Tomori, Davide Calabria, Ante Rebic and Mike Maignan, and that told in a poor display.
A mix-up between back-up goalkeeper Ciprian Tatarusanu and Matteo Gabbia gifted Joseph Alfred Duncan the opening goal, which ex-Milan player Riccardo Saponara added to before half-time.
Dusan Vlahovic also scored twice, either side of a Zlatan Ibrahimovic double that had set up a tense period in the game, before Lorenzo Venuti put into his own net from the last action of the game.
Milan have now taken just one point from their last two games, having previously been held by Inter, but Pioli is hopeful his side will bounce back.
"We have to feel the pain of this defeat and make sure it doesn't happen again," he told Sky Sport Italia. "Even in this defeat I am convinced that I have a very strong team.
"We have to learn from this. Losing hurts, as does conceding four goals. We showed that we are able to recover, but perhaps we could have done without conceding the fourth.
"The team played as a team and with rhythm. Sometimes we missed the last pass. We had twice as many shots as our opponents, so the performance was there.
"We are sorry because after the international break we wanted to restart with a victory."
Ibrahimovic became the oldest player – and the first over 40 – to score two or more goals in a single game in Europe's top five leagues this century with his double.
However, Vlahovic stole the show with a brace of his own as he made it 27 Serie A goals in 2021, equalling Kurt Hamrin (in 1960) for the most in a calendar year for Fiorentina
Indeed, only Bayern Munich striker Robert Lewandowski (38) has scored more goals than Vlahovic (27) since the start of 2021 in the big five European leagues.
The Serbia international has been linked with a number of the continent's big-name clubs, but Viola boss Vincenzo Italiano wants his side to make the most of the rising star while they can.
"Right now he is a player destined for an important career, not only because he knows how to score but because of how he trains," Italiano told Sky Sport Italia.
"If he stays this same player he is destined for a great career. I don't know what his future will be, but for now we enjoy it. In this game he was loaded with buckshot and I'm happy for him."