Lautaro Martinez's goal in the 92nd minute was what Inter Milan needed in a contest between the second and third placed clubs in Serie A.
Inter, with 36 points from 18 matches, moved to within 5 points of second placed Napoli, who saw the gap to leaders Juventus widen to 9 points, reports Efe.
The hosts were the bolder side in the first half here on Wednesday and appeared to have taken the lead in the 30th minute with a strike by Ivan Perisic, but the goal was disallowed for an offside, while Napoli defender Kalidou Koulibaly made a goal-line stop against Mauro Icardi to preserve the 0-0 heading into the break.
Napoli, who lost captain Marek Hamsik to an injury in the first half, improved after the re-start only to see their prospects dim in the 78th minute with the expulsion of Koulibaly.
The Senegalese international picked up two yellow cards in 30 seconds: the first for a foul against Matteo Politano and the second for mocking the referee.
Martinez, who came on with eight minutes left, broke the deadlock in stoppage time before Napoli's Lorenzo Insigne was sent off with a straight red card, apparently for dissent.
Napoli coach Carlo Ancelotti was fuming after the match about alleged racist chants directed at Koulibaly.
The visitors asked on three separate occasions for play to be suspended, the coach said.
"The next time we'll stop playing, even if we lose the match," Ancelotti added.
--IANS
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