Jose Callejon finally got the better of Gianluigi Buffon midway through the first half before Dries Mertens’ brilliant finish with 10 minutes remaining clinched the match, as Italy’s likely champions suffered just their second defeat of the campaign.

Buffon was perhaps the busiest player on the pitch over the course of the 90 minutes, saving twice from Callejon in the first half before producing breathtaking acrobatics to deny Marek Hamsik and Faouzi Ghoulam on either side of the break.

Despite the defeat, Antonio Conte’s side remain 11 points clear at the top of the table, although AS Roma can reduce that margin to eight if they win their game in hand.

Napoli’s hopes of qualifying for the Champions League are enhanced by the triumph, however, as they now lead Fiorentina by 12 points in the race for third.

They are also just six points behind Roma, keeping alive the possibility of finishing second and avoiding a play-off to enter Europe's most lucrative competition.

"This is a very important win, because it keeps us close to Roma," Napoli's Lorenzo Insigne said, per AP. "We're going to fight until the end."