Debutant Lorenzo Tonelli scored deep into stoppage time as third-placed Napoli came from a goal behind to defeat 10-man Sampdoria 2-1 in Serie A.
Matias Silvestre's controversial red card proved a turning point, as the lead given to the visitors by Elseid Hysaj's own goal after 30 minutes evaporated under intense pressure.
Napoli – who had scored 16 goals in their previous four league matches – had been wasteful in front of goal, with Dries Mertens particularly guilty.
But Silvestre's dismissal just after the hour-mark for two quick bookings, the second of which came after he made minimal contact with goalkeeper Pepe Reina, gave the hosts renewed impetus.