AC Milan bounced back from last week's defeat at Hellas Verona with a 3-1 win at home to Cagliari in an entertaining evening featuring 32 goals in eight games.
It was one-way traffic in Sicily as Walter Mazzari's Inter showed that they have put last season's troubles behind them.
Alberto Aquilani give Vincenzo Montella's Fiorentina the lead at Genoa after 10 minutes before Giuseppe Rossi scored his second in as many games four minutes later and Gomez tapped in his goal four minutes before the break.
Alberto Gilardino gave the home side some hope nine minutes after the break with a stunning volley, but Rossi tapped in his second almost immediately afterwards.
Francesco Lodi reduced the deficit again on the hour with a penalty following a foul on Gilardino, but an injury time penalty from Mario Gomez ruined Genoa's celebrations for their 140th anniversary, in which cricket was played on the Stadio Luigi Ferraris pitch before the match.
The club's official name is Genoa Cricket and Football Club, and it has a cricket team which was re-established in 2007 and plays in Italy's top division.
Goals from Robinho, Philippe Mexes and Mario Balotelli were enough for AC Milan against a plucky Cagliari team.
Brazilian Robinho and Mexes put Massimiliano Allegri's side two goals up after half an hour, only for Marco Sau to pull one back for the away side three minutes later.
However, Balotelli's first league goal of the season in the 62nd minute put the result beyond doubt.
Earlier on Sunday Roma moved into second place on goal difference after splendid goals from Miralem Pjanic and Adem Ljajic gave them a comfortable 3-0 win over newly promoted Hellas Verona.
Rudi Garcia's side moved to six points after Bosnia international Pjanic's delightful chip from more than 20 metres out in the 59th minute and a powerful long range drive from Ljajic on his Roma debut six minutes later.
The home side were playing with the Curva Sud section of the Olympic Stadium shut after racist chanting directed at Balotelli from hardcore fans at the end of last season.