Match ends, Napoli 4, Inter Milan 2.
Napoli inflicted 10-man Inter Milan's second Serie A defeat of the season in a gripping match at Stadio San Paolo.
A five-goal first half saw Gonzalo Higuain volley Napoli in front only for Esteban Cambiasso to equalise.
Rafael Benitez's men went two-goals up after Dries Mertens and Blerim Dzemaili struck, only for Yuto Nagatomo to give Inter hope with a tap-in.
Ex-Napoli boss Walter Mazzarri's loss was secured when Jose Callejon pounced after Ricky Alvarez was dismissed.
Benitez, who was sacked by Inter after a difficult six-month spell in 2010, was also facing his former club
The Spaniard also had to deal with his side's midweek Champions League exit after being denied knockout stage qualification by Borussia Dortmund despite beating Arsenal 2-0.
Regardless, the result saw third-placed Napoli open up a seven-point gap to their fifth-placed opponents. This difference could prove valuable in the months ahead as third is the final qualifying spot for Europe's premier club competition in the Italian top flight.
Mazzarri's return to Naples after deciding to end a four-year spell in charge this summer appeared to be going well when his new team started the brighter, only for Higuain to volley in expertly after latching on to a sloppy Nagatomo header in the host's opening attack.
Cambiasso levelled things after sweeping home a flowing counter-attack, only for Mertens to fire in first time from the edge of the box and Dzemaili to double the advantage after reacting quickest to a fine Samir Handanovic save.
Nagatomo then made amends for his poor defensive error with a tap-in following a smart cross from the impressive Fredy Guarin, before the referee called time on a thrilling first 45 minutes.
Inter's push for an equaliser was tempered with 20 minutes to play as midfielder Alvarez was harshly dismissed for a second booking after handling the ball.
With the Nerazzurri now weakened, former Real Madrid forward Callejon found his seventh league goal of the season after being presented with the easiest of finishes by Lorenzo Insigne's drive across goal.
There was even time for ex-Inter man Goran Pandev to miss a penalty before the final whistle signalled an impressive victory for Benitez's challengers.
- 2RéveillereSubstituted forPandevat 90+1'minutes
- 88InlerBooked at 32mins
- 9HiguaínSubstituted forBehramiat 78'minutes
- 14MertensSubstituted forArmeroat 86'minutes
- 24InsigneBooked at 29mins
- 2Cicero Moreira
- 35Da Fonseca
- 23RanocchiaBooked at 90mins
- 14CampagnaroSubstituted forIcardiat 82'minutes
- 21Sliti TaiderSubstituted forKovacicat 61'minutes
- 11ÁlvarezBooked at 71mins
- 5Nunes Jesus
- Paolo Tagliavento
- Shots on Target
Second Half ends, Napoli 4, Inter Milan 2.
Corner, Napoli. Conceded by Samir Handanovic.
Penalty saved! Goran Pandev (Napoli) fails to capitalise on this great opportunity, left footed shot saved in the bottom right corner.
Andrea Ranocchia (Inter Milan) is shown the yellow card for a bad foul.
Penalty conceded by Andrea Ranocchia (Inter Milan) after a foul in the penalty area.
Penalty Napoli. Goran Pandev draws a foul in the penalty area.
Substitution, Napoli. Goran Pandev replaces Anthony Réveillere.
Attempt missed. Blerim Dzemaili (Napoli) right footed shot from outside the box is just a bit too high. Assisted by José Callejón.
Substitution, Napoli. Pablo Armero replaces Dries Mertens.
Attempt missed. Dries Mertens (Napoli) right footed shot from the right side of the box is close, but misses to the right. Assisted by José Callejón with a cross following a fast break.
Substitution, Inter Milan. Mauro Icardi replaces Hugo Campagnaro.
Goal! Napoli 4, Inter Milan 2. José Callejón (Napoli) right footed shot from very close range to the centre of the goal. Assisted by Lorenzo Insigne.
Attempt blocked. Rodrigo Palacio (Inter Milan) right footed shot from the right side of the box is blocked. Assisted by Hugo Campagnaro.
Substitution, Napoli. Valon Behrami replaces Gonzalo Higuaín.
Foul by Yuto Nagatomo (Inter Milan).
Christian Maggio (Napoli) wins a free kick on the right wing.
Offside, Inter Milan. Andrea Ranocchia tries a through ball, but Jonathan is caught offside.
Corner, Inter Milan. Conceded by Anthony Réveillere.
Fredy Guarín (Inter Milan) wins a free kick in the defensive half.