Ciro Immobile’s superb first-half finish gave the hosts a deserved lead after 25 minutes, but the visitors were jolted into action by the setback and turned the result around with strikes from Arkadiusz Milik and Insigne either side of the break.
Italy international Immobile latched onto a long ball from Francesco Acerbi, and a drop of the shoulder and swivel of the hips later, three Napoli defenders were clutching at air as the striker buried a curling left-footed finish into the far corner.
Lazio’s lead was deserved, but the goal sparked life into Ancelotti’s men. The lively Piotr Zielinski dipped a shot onto the crossbar, before Lazio failed to clear their lines from a corner and Marek Hamsik’s early strike was parried by Thomas Strakosha into the path of Milik, who tapped home.
However, the goal was overturned after a VAR review ruled that Stefan Radu was fouled by Kalidou Koulibaly. The cheers of the home fans lasted only a few minutes though, as Napoli’s front three combined to give them a leveller. Insigne’s cross found Jose Callejon at the back post and the Spaniard squared to tee Milik up for a close-range finish.
The visitors then completed the comeback on the hour, when Allan helped on an Elseid Hysaj cross from the right directly into the path of Insigne. The winger made no mistake, lashing a fierce finish into the top corner to put them in the driving seat.
Late pressure from Lazio was very nearly rewarded at the death when Acerbi saw his header come back of the post from point-blank range, as Napoli held on to secure a valuable three points and give Ancelotti a dream debut.