Napoli squandered a two-goal halftime lead, then scored two late goals to beat nine-man AC Milan 4-2 in a stormy Serie A match which saw eight other players booked on Saturday.
Earlier, champions Juventus won 1-0 at Lazio for their second straight win of the new season.
Poland striker Arkadiusz Milik, signed to replace Gonzalo Higuain after last season's Serie A topscorer moved to Juventus in a 90 million euro move, scored twice in the first half to put Napoli in control.
M'baye Niang and Suso hit back in a four-minute spell early in the second half to pull Milan level but Jose Callejon put Napoli back in front in the 74th minute.
Juraj Kucka was sent off after he was booked for a push on Dries Mertens and immediately given another yellow card for swearing at the referee.
Then Niang was given a second yellow card for pushing Napoli goalkeeper Pepe Reina before Alessio Romagnoli turned Lorenzo Insigne's shot into his own goal to complete Milan's misery.
Lazio continued an unhappy run against Juventus in the earlier game at the stifling Stadio Olimpico, where the match was halted for a water break in the 28th minute.
Sami Khedira settled the game in the 66th minute to extend Juve's 13-year unbeaten run against Lazio, while coach Massimiliano Allegri enjoyed the luxury of starting Higuain and fellow new signing Miralem Pjanic on the bench.
