Youth movement: Locatelli, Donnarumma lead Milan's resurgence

The 1-0 win was official. AC Milan just beat Juventus at a sold-out San Siro, and its teenage match-winner could hardly believe it was reality.

Just 18 years old, Manuel Locatelli scored a goal Saturday that will be remembered for ages. Making only his third career start for the Rossoneri, he thumped a rocket of a shot past Gianluigi Buffon to break the deadlock and clinch Milan's first triumph over the Bianconeri since November 2012.

Related - Watch: Milan's Locatelli fires stunning winner vs. Juventus

"I still haven't quite realised what I've done. I just scored against the best goalkeeper in the world," Locatelli told Mediaset Premium in astonishment.

For years, Milan was a laughing stock of Serie A, a fallen giant that showed no signs of progress. Stars left the club under the guise of balancing the books. Young players barely got a chance as older free agents took their spots. The stadium sat empty for matches on end, the result of fan-driven protests against an aging and complacent owner.

But now this team is one of the most promising in Europe, with an average age below 25 years. Manager Vincenzo Montella - hired in the summer following a carousel of hirings and firings - has worked out a winning formula with players who want to give everything for the shirt.

The difference is that Montella's Milan has an identity. It plays as a unit. And if you're good enough, you're old enough.

Related - Litmus test: Juventus clash will show how far Montella's Milan has come

If we want to be technical, the youth movement started last season with Sinisa Mihajlovic's bold decision to start Gianluigi Donnarumma ahead of veteran Diego Lopez. Then 16, Donnarumma would solidify the No. 1 spot for the rest of the campaign - even as Mihajlovic eventually faced the sack. Though the Serbian tactician didn't last a year at the club, Donnarumma is his legacy.

The Italian prodigy was an important piece of Saturday's victory. Making three saves in total, he parried away Sami Khedira's last-minute attempt to equalise the match. The game ended with that miraculous stop, and his teammates swarmed him.

Donnarumma may have bailed them out this time, but it was truly a team effort.

Montella has cultivated an environment of togetherness after so many years of fearful play. There is strength in numbers, not only in the way Milan defends but also in the way it celebrates. This is a team that leans on one another.

There were times in this match when Milan seemed to give Juventus far too much space. Alex Sandro often had the freedom to whip in crosses without hassle.

There was also Nicola Rizzoli's dubious decision to call back Miralem Pjanic's early free-kick.

But Milan congested the middle of the pitch and gave nothing else for free. Alessio Romagnoli - himself only 21 - and Gabriel Paletta - one of Milan's elderly statesmen at 30 - cleared almost every threatening ball.

The ones that went through were gobbled up by Donnarumma.

Locatelli gave his defenders as much support as possible. At times, he dropped so deep that it gave the impression Milan had a back three. He protected the ball from Juve's advances, and slipped passes into open channels.

His goal rightfully won the headlines, but his overall performance was the most convincing.

His emotions also tell a story: When he scored a goal of similar gravity and drama in a 4-3 win over Sassuolo, he couldn't hold back the tears. He sobbed through a post-match interview.

Playing for Milan is special again.

Related - Locatelli stunned at beating Buffon: 'I still can't believe it'

Just two points behind Juventus in the Serie A standings, Montella and his players have every reason to take pride in what they're doing. The manager grew up as a Milan supporter, and when he saw the celebrations under the famous Curva Sud, he felt something.

"To be honest, tonight I was really emotional," he told Sky Sport, according to Milan News. "To see the lads celebrating under the Curva, it brought back memories of my adolescence when I was a fan of Milan."

Now he is leading his childhood club back to relevance.