Defender Gabbia rose highest to thump home Tijjani Reijnders' free-kick in the 89th minute and give Milan a Serie A win which pulls them out of a miserable early season slump.
Juventus were held to a 0-0 Serie A draw at Empoli on Saturday as Thiago Motta's side dropped more points after their goalless home stalemate against AS Roma before the international break.
Inter and AC Milan on Friday rejected the project to modernise and restructure the iconic San Siro stadium which they share, city mayor Giuseppe Sala announced.
Victor Osimhen has been sidelined by Napoli after the team he fired to Serie A glory just a over year ago left him both off their squad list for the 2024/25 campaign and potentially in season-long limbo.
Belgium striker Lukaku completed a permanent move to Napoli from Chelsea on Thursday, ending a long period of limbo with the Blues.
Inter Milan thrashed Atalanta 4-0 on Friday to move provisionally top of Serie A, while Torino snatched a late 1-0 win at Venezia to continue their positive start to the campaign.
The futures of Napoli striker Victor Osimhen and England international Ivan Toney are set to dominate the final day of the European transfer window on Friday as Chelsea continue their frenzied pursuit of new signings.
Napoli have signed Romelu Lukaku from Chelsea, the Serie A club announced on Thursday, ending the Belgium striker's extended period in limbo with the Blues.
Poland goalkeeper Wojciech Szczesny on Tuesday announced he was retiring from football at the age of 34 less than two weeks after the end of his contract with Juventus.
Earlier, the Italian Football Federation's (FIGC) appeals court announced Juve's 10-point deduction. The decision came following a revision of their initial 15-point penalty inflicted on the club over illicit transfer activity.
Juventus midfielder Paul Pogba vowed Sunday to give his all to return next season at his best after a trying time both on and off the pitch.
Milan ended a run of three straight defeats, including two at the San Siro against Inter in the Champions League semi-final, with an emphatic victory over a team dead last in the table
AC Milan coach Stefano Pioli hopes to have Rafael Leao back for Tuesday's Champions League semi-final, second leg against city rivals Inter in which the Rossoneri will attempt to overturn a 2-0 deficit.
Paul Pogba's injury-blighted season is ending as it started with the French midfielder out for two to three weeks after tests Monday revealed a thigh injury.
Pogba, who returned to Juventus last summer but has struggled with injury since, began the game well as he started a match for the first time since last April when he played for Manchester United at Liverpool
A Romelu Lukaku brace on his 30th birthday, a further strike from Lautaro Martinez and an unfortunate Ruan Tressoldi own goal were enough for Inter to claim a seventh straight win in all competitions and move level on 66 points with second-placed Juventus
Rafael Leao misses out on the first leg of AC Milan's Champions League semi-final with Inter Milan after not recovering from a thigh injury in time for Wednesday's match.
The 24-year-old is now the highest scoring African player in the history of Serie A after overtaking George Weah and lapped up the applause of Napoli fans as the team did their post-match lap of honour
AC Milan and Inter Milan secured matching 2-0 victories over Roman clubs as they briefly swopped places in Serie A ahead of their Champions League semi-final clash.