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'
|Mourinho hints at United future for Mata and Fellaini|
|Real Madrid 3 Chelsea 2: Hazard show too late for Blues|
|Penalty woes for Everton, Gray treble inspires Burnley at Ibrox|
|Atleti to present Gameiro on Sunday|
|Ibrahimovic nets debut goal as United put five past Galatasaray|
|Barcelona 3 Celtic 1: Messi, Suarez in action as Catalans cruise to victory|
|WATCH: Zlatan open his Man Utd account with acrobatic goal|
|Alba: It would be foolish not to respect Ronaldo, but Messi on another level|
|Lahm hails ´sensational guy´ Schweinsteiger following Germany retirement|
|Stones´ professionalism praised amid City reports|
|Roma suffer Rui blow|
|Inter complete Ansaldi move|
|Nainggolan confident of Roma challenge despite Juve investment|
|Rummenigge tells off Ribery over Guardiola dig|
|Meli makes Sporting loan switch|
|No repeat of slow start, vows Allegri|
|Mourinho desperately wanted Embolo at Manchester United, claims Heidel|
|Dembele can do anything - Tuchel|
|Pogba arrival would boost Rooney - Yorke|
|Ben Yedder makes Sevilla move|
|De Jong signs PSV renewal until 2020|
|Kovacic to fight for his place at Real Madrid|
|Sturridge out to improve goals-per-game ratio|
|Mourinho hails ´humble´ Ibrahimovic ahead of United debut|
|Schweinsteiger will not leave Manchester United for Bundesliga return - Rummenigge|
|Benatia on target again in Juve win|
|Atletico set to sign Gameiro|
|Zenga appointed Wolves boss|
|Flattered Verratti not seeking Madrid move|
|Ancelotti: Growing transfer fees nothing special|
|Eriksson: Ibrahimovic and Mourinho combo enough to win Premier League|
|Meunier: I could not reject PSG|
|Klopp: I didn´t want Mkhitaryan|
|Anything could happen before transfer window shuts - Zidane|
|Montoya leaves Barca base, nears Valencia switch|
|Wijnaldum: I´m happy to play anywhere|
|Klopp backs Mignolet after Karius injury|
|Liverpool suffer Karius injury blow|
|Ranieri confident Mahrez will stay as contract talks continue|
|Emery confirms interest in Jese|
|Higuain´s Juventus move not about money - agent|
|Wolves sack head coach Jackett|
|Zidane: Ronaldo unlikely to play Madrid La Liga opener|
|Ibrahimovic: United fans are waiting for me|
|Deulofeu shines for Everton, Cook opens Bournemouth account|
|Higuain out to emulate Del Piero|
|Kante does his talking on the pitch - Conte|
|Mourinho explains Fosu-Mensah snub|
|Klopp: No more unwanted players at Liverpool|
|Inter want more than €60m for Icardi - Thohir|
|Leicester can replace Kante - Ranieri|
|Lazio complete Wallace signing|
|Gueye set to join Everton, confirms Di Matteo|
|Tuchel: Transfer market has gone cash crazy|
|Leicester hand King new four-year deal|
|No deal done for Pogba, says Raiola|
|Rooney: Mourinho impact already huge|
|Lafferty hit with FA betting charge|
|Top-four finish never enough for Arsenal, insists Wenger|
|Partey hoping to make his mark on Atletico squad|
|Ibrahimovic in, Schweinsteiger out as United head for Galatasaray friendly|
|Vietto set for Sevilla after completing medical|
|I rejected Besiktas to fight for Barcelona spot, reveals Mathieu|
|De Laurentiis fumes at Higuain´s ´lack of respect´|
|Promising Janssen boosts Tottenham´s title hopes|
|Besiktas sign Adriano on three-year contract|
|Tottenham 0 Atletico Madrid 1: Godin grabs the winner|
|Gomis completes Marseille loan move|
|Iniesta surprised at Casillas-Del Bosque spat|
|New Juve signings do not guarantee success - Allegri|
|New Juve signings do not guarantee success - Allegri|
|Middlesbrough snap up goalkeeper Guzan|
|Guardiola still loves Ribery despite jibes|
|West Ham worry over Tore injury|
|Serie A could be another one-horse race, says Eriksson|
|Schweinsteiger retires from Germany duty|
|Iniesta welcomes Barca´s midfield competition|
|Drogba: No luck in Arsenal scoring record|
|Wenger seeks ´experienced´ striker to bolster Arsenal attack|
|Eriksson and Shanghai SIPG still fighting|
|MLS All-Stars 1 Arsenal 2: Premier League giants win late as Xhaka makes debut|
|Conte: I want aggression and intensity|
|Wimmer backs physical Janssen for Tottenham success|
|Klopp: I wouldn´t spend £100m on one player|