Maurizio Sarri responded to a question by a female journalist by saying "I won't tell you to f*** off" as Napoli suffered another damaging result in the Serie A title race.
Having seen Juventus go two points clear at the top with a 2-0 win over Udinese on Sunday, Napoli, who have led the way for much of a superb season under Sarri, failed to respond in their game with Inter.
Sarri's men were held to a 0-0 draw at San Siro, giving Juve a one-point lead with a game in hand.
Asked if Napoli's title hopes were over after the match, Sarri replied: "You're a woman, you're nice, so I won't tell you to f*** off."
Sarri reportedly immediately apologised to the journalist after his media conference.
Napoli will look to get back on track when they host Genoa on Sunday.