Napoli, runners-up in three of the last four seasons, 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. Napoli were also awarded a controversial penalty, for a foul on Dries Mertens, which left Fiorentina coach Vincenzo Montella fuming especially after Franck Ribery, making his debut for the hosts, had a penalty appeal turned down late in the game.