Champions Juventus and AC Milan both recorded wins, but Napoli are top of Serie A as three goals in five second-half minutes helped earned a fine 4-1 win at Lazio.
The hosts were leading after half an hour when Ciro Immobile jinked his way to the byline and pulled the ball back for Stefan de Vrij to sweep home.
But nine minutes after the break Kalidou Koulibaly hauled Napoli back in it when he swept home after Lazio failed to clear a corner.
Two minutes later Jose Callejon fired the visitors into the lead and in the 59th minute a long-range drive from Dries Mertens left Lazio stunned. Jorginho added the fourth with a penalty in injury time.
Napoli lead Juventus on goal difference after they too made it a perfect five wins out of five so far this season. Mario Mandzukic fired the reigning champions to a 1-0 victory over fierce rivals Fiorentina in Turin.
The Croatian hitman struck early in the second half with a diving header from Juan Cuadrado's cross.
Fiorentina finished the game with 10 men after Milan Badelj was sent off with 25 minutes remaining.
Juve thought they had been awarded a penalty after Badelj tripped Blaise Matuidi as he attempted to race into the area. But after consulting with the video replays, the referee decided the initial contact had taken place outside the box.
The decision was not enough to save Badeji from a second yellow card, but Juve wasted the free kick and then had to withstand some late pressure for a narrow victory.
AC Milan needed a penalty in each half to see off SPAL 2-0.
Alfred Gomis felled Nikola Kalinic for the first spot kick, which Ricardo Rodriguez tucked away after 25 minutes. Franck Kessie converted the second just after the hour mark after he had been brought down by Felipe.
Edin Dzeko scored twice as Roma piled on the misery for rock-bottom Benevento with a 4-0 victory.
The hosts, still looking for their first Serie A points, did not help themselves by contributing two own goals from Fabio Lucioni and Lorenzo Venuti.
Atalanta made short work of lowly Crotone with a thumping 5-1 victory. Andrea Petagna tapped in Josip Ilicic's cross for the opener and Mattia Caldara headed the second before Ilicic made it 3-0 before half-time.
Alejandro Gomez hit the fourth and Marco Tumminello pulled one back before Gomez completed the scoring from the penalty spot.
Torino won 3-2 at Udinese thanks to strikes from Andrea Belotti, an Emil Hallfredsson own-goal and Adem Ljajic. Rodrigo De Paul, from the penalty spot, and Kevin Lasagna replied for the hosts.
Alessandro Matri scored the decisive penalty as Sassuolo sank Cagliari 1-0.
Diego Laxalt put Genoa 1-0 up against Chievo but Perparim Hetemaj replied to secure a 1-1 draw, while Verona were held to a goalless draw at home to Sampdoria.