Napoli, last season's runners-up, hit back from conceding a contentious early penalty to win 4-3 at new-look Fiorentina in a hugely entertaining start to their Serie A campaign on Saturday.

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Fiorentina's new signing Erick Pulgar scored in the ninth minute from a penalty awarded with the help of a long VAR review after the ball was kicked against the arm of Piotr Zielinksi at point-blank range

Dries Mertens levelled with Napoli's first real attack of the game in the 38th minute and then won a penalty, which was also controversially awarded and converted by Lorenzo Insigne, five minutes later.

Nikola Milenkovic headed Fiorentina back on level terms in the 52nd minute only for Jose Callejon to put Napoli back in front four minutes later.

Substitute and new signing Kevin-Prince Boateng equalised for Fiorentina in the 65th minute and Insigne headed the winner for Napoli two minutes after that.