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.
Inter Milan slumped to a 1-0 home defeat by Fiorentina on Saturday as Giacomo Bonaventura's second-half goal dealt a blow to their hopes of qualifying for the Champions League from Serie A.
The face of a young Diego Armando Maradona gazes down from a mural in Naples' Miracles Square, watching the city gear up for a celebration it hasn't enjoyed since the Argentine soccer star was at his peak more than 30 years ago.
While the fans of Italian football continue to struggle to convince their peers from the English Premier League and LaLiga about the relevance of Serie A in European footballing hierarchy, it is with a renewed optimism that they can now boast about Napoli – the new entertainers of European football.
Juventus maintained their slim hopes of making it to next season's Champions League when Filip Kostic's goal earned them a 1-0 win at Inter Milan in Serie A on Sunday.
Serie A leaders Napoli thrashed Torino 4-0 away with a double from Victor Oshimen and goals from Khvicha Kvaratskhelia and Tanguy Ndombele on Sunday to move closer to the title.
Both have struggled with injuries this season and Allegri said on Saturday they could join Leonardo Bonucci, Alex Sandro, Arkadiusz Milik and Paul Pogba as injury absentees
Milan missed the chance to jump to second and remained fourth with 48 points, a point clear of fifth-placed AS Roma, who play Lazio on Sunday
The 11th goal of the Georgian's debut Serie A season came in the 60th minute of Saturday's game, as he slalomed his way into the penalty area and left defenders floundering before burying a fierce finish into the roof of the net.
Inter Milan missed the chance to cut Napoli's huge lead at the top of Serie A on Friday after suffering a shock 2-1 defeat to relegation-threatened Spezia.
Juventus forward Federico Chiesa sustained a knee injury in the 1-0 home win over Germany's SC Freiburg in the Europa League on Thursday, coach Massimiliano Allegri said.