Gonzalo Higuain scored twice to give Napoli their first win in four Serie A games as Milan were beaten 3-1 at Stadio San Paolo.
Adel Taarabt's debut goal had given Clarence Seedorf's Milan an early lead on Saturday, but Napoli were not to be denied a deserved victory.
Gokhan Inler equalised soon after, and Higuain struck twice after half-time to take his Serie A goal tally to 12 for the season and give Rafael Benitez's men their first league win since a 3-0 triumph at Verona on January 12.
Napoli, who were beaten by Atalanta in Serie A last weekend and Roma in semi-final of the Coppa Italia in midweek, dominated from start to finish and are now only three points behind second-placed Roma - who have two games in hand.
Defeat for Milan was their first in the league since Seedorf took over as coach last month, but the Dutchman may count his blessings that his side were not beaten by a more handsome margin.
Napoli defender Faouzi Ghoulam replaced the injured Anthony Reveillere and Dries Mertens came in for Jose Callejon, who started on the bench along with January signing Henrique.
Michael Essien and Taarabt made their Milan debuts, while striker Mario Balotelli returned from suspension as Seedorf made six changes to the side that drew with Torino last weekend.
Napoli made a bright start, but they were caught out after only seven minutes when QPR loanee Taarabt raced forward before placing a measured right-foot strike into the far corner of the net from just outside the area as the home defence backed off.
The goal was harsh on Benitez's team, but they were level three minutes later courtesy of a fine left-foot strike from Inler that took a deflection and looped over Christian Abbiati.
Milan struggled to cope with Napoli's attacking threat, and Higuain was inches away from putting the home side in front when his shot flashed wide of the far post.
Abbiati was lucky to escape with only a yellow card after 22 minutes when he rushed out of his area and upended Mertens after the winger had raced onto a through ball and attempted to lob the veteran goalkeeper.
To add insult to injury, Abbiati kept out the resulting free-kick from the Belgium international, before Marek Hamsik's venomous left-foot volley flashed just wide.
Christian Maggio then hit the post from a tight angle and Lorenzo Insigne headed just wide as Milan somehow went in level at the break.
Kaka replaced fellow Brazilian Robinho at half-time, but his introduction failed to turn the tide as Napoli maintained the upper hand and Abbiati could only watch on as Insigne's strike flashed wide.
It was only a matter of time before the home side took the lead, and it was former Real Madrid man Higuain who put them in front when he headed home an inviting cross from Inler 11 minutes into the second half.
The Argentina striker was a constant menace and he ought to have given Napoli breathing space but missed his kick after evading the vulnerable Philippe Mexes.
Napoli could have been made to pay for not making their dominance count but Taarabt's strike was kept out by Pepe Reina and then Balotelli failed to capitalise after the Spanish goalkeeper had totally missed his kick.
Higuain sealed the points with eight minutes left, though, slotting home from close range after Callejon picked him out.
|88||G. İnler||11' 38'|
|9||G. Higuaín||56' 82'|
|Coach: Rafael Benítez|
for L. Insigne 78'
for M. Hamšík 83'
for G. İnler 89'
|UEFA Champions League Review: Ajax crash out after home defeat|
|Blackpool handed suspended deduction|
|Bayern Munich 3 Milan 0: Guardiola and De Jong lock horns in tunnel|
|Akpom, Ojo and Solanke on the move|
|McClaren: No Newcastle bid for Austin|
|Real Madrid 2 Tottenham 0: Bale on target against former club|
|Mangala vows to improve on debut campaign|
|Tomlin completes Bournemouth switch|
|Astra v West Ham: Page hungry for first-team action|
|Di Maria arrives in Qatar for PSG medical|
|Vitesse v Southampton: Caulker prepared to wait for his chance|
|UEFA rejects Fenerbahce´s Fred appeal|
|Watford show support for assaulted fan as police charge six|
|Ibrahimovic to miss PSG opener|
|Klopp suited to Bayern job - Watzke|
|Eredivisie season-opener postponed due to police strike|
|Dortmund v Wolfsberger: Tuchel set for home bow|
|Griezmann at the double in Atletico win|
|Japan v South Korea: Halilhodzic calls for ´pride´|
|Mourinho enjoying improved relationship with Abramovich|
|Gradel agrees Bournemouth return|
|Inter switch an ´easy decision´ for Miranda|
|Bojan eyes early comeback|
|Vitesse hopeful over Solanke loan deal|
|Pedro will decide his own future - Luis Enrique|
|Iniesta handed Barcelona armband|
|Kukesi punished after Europa League abandonment|
|Leno hints at Leverkusen exit|
|Benitez explains Ronaldo absence|
|Pochettino backs Kane to be among world´s best|
|Messi not ruled out of Mexico friendly - Martino|
|China v North Korea: Kim´s side look for another win|
|River Plate v Tigres UANL: Copa Libertadores final evenly poised|
|Real target Ceballos focused on Betis - Mel|
|Torres: I´d give my life to win La Liga with Atletico|
|Platini can lead FIFA change - Fernandez|
|Mel: Betis won´t be signing Osvaldo|
|Ferrero defends Samp boss Zenga|
|Pochettino expects Spurs improvement|
|Bale ideal for United - Robson|
|Ferdinand: Di Maria will regret United failure|
|Benitez pleased with goalkeepers as De Gea transfer saga continues|
|Guardiola tips fit Schweinsteiger to shine|
|Confident Oxlade-Chamberlain hits back at Keane|
|Ferdinand: Stones would be ´a lunatic´ to join Chelsea|
|Qarabag v Celtic: Gordon wants positivity from Scottish champions|
|Higuain rejects extension from Napoli|
|Zamora returns to Brighton|
|West Ham can cope without Valencia - Gold|
|Wickham loses on Palace debut|
|Guardiola: No problem with Matthaus and Effenberg comments|
|Cartabia excited by Deportivo loan|
|Lyon confirm Rafael deal|
|Hysaj agrees deal to follow Sarri to Napoli|
|Rafael says his goodbyes to Manchester United|
|Dos Santos ready to get going with Galaxy|
|Pochettino rejects Soldado exit talk|
|Metatarsal misery for Mulumbu|
|Benitez: Benzema and Bale going nowhere|
|Mihajlovic: Ibrahimovic would make Milan title contenders|
|Hughes not taking any risks with Bojan|
|Guardiola relishing Audi Cup test|
|Di Maria ´taking a step up´ - Silva|
|Leicester bring in defender Benalouane|
|Deulofeu doubtful for Premier League opener|
|West Ham striker Valencia out for three months|
|UEFA: Qarabag-Celtic to go ahead|
|Palace seal Wickham swoop|
|Ronaldo and Benzema to miss Audi Cup|
|Marotta: Juventus could lose Pogba|
|Kante completes Leicester switch|
|Khedira ruled out for two months|
|FA accepts Mourinho criticism of Wembley surface|
|Robben rubbishes injury talk|
|Marchisio expects Milan title challenge|
|Rafael set for Lyon move|
|Celtic ´seeking reassurances´ over Qarabag pitch|
|Wenger beating Mourinho does not affect Chelsea - Zouma|
|Rooney moved by Everton welcome|
|Mancini not worried by lack of Inter goals|
|Coloccini wants to finish career at Newcastle - McClaren|
|Ramsey: Pressure to win trophies is nothing new|
|Terry: Wembley defeat could be a ´blessing in disguise´|
|Blatter not running for IOC re-election|
|Bendtner: Wolfsburg can challenge Bayern for Bundesliga honours|
|Liverpool relishing Britannia return, says Henderson|
|Everton big enough to keep Stones - Martinez|
|MLS Review: Fire stun Dallas as goals dry up|
|New Atletico signings excite Raul Garcia|
|Cahill expects Arsenal title challenge|
|Jovetic happy with Inter debut|
|Luis Enrique: Barca defence must improve|
|Yanev calls for calm after ugly scenes in friendly|
|Coppa Italia Review: Cittadella romp to victory, Brescia rely on penalties|