Napoli’s victory lifts them to fourth place in Series A, ahead of Roma and Lazio on goal difference.
With this victory, Napoli opens up the race for the Series A title by doing the two Milan sides a favour.
They’re just two points behind Juventus now, who stay five points behind Inter and seven behind league leaders AC Milan.
Insigne’s penalty helped Napoli beat Juventus in two consecutive league games for the first time since 2011, putting a dent on Juve’s title run.