Gennaro Gattuso suffered defeat in his first game in charge of Napoli at home to Parma thanks to a stoppage-time winner from Gervinho.
The former Arsenal striker struck three minutes into added time to secure the victory after Napoli forward Arkadiusz Milik had cancelled out Dejan Kulusevski’s early opener.
In a move that sent shockwaves in Serie A, Gattuso succeeded Carlo Ancelotti as Napoli head coach on Wednesday.
The Neapolitans drop to eighth and are now without a win in eight Serie A matches.
Ancelotti was sacked on Tuesday evening, less than three hours after he guided them into the Champions League knockout stages with a 4-0 victory over Genk.
The 60-year-old former AC Milan and Chelsea boss has been linked with the managerial vacancies at Arsenal and Everton.