Mauro Icardi scored a hat-trick and Pablo Osvaldo added a brace as Inter routed Sassuolo 7-0 for the second successive season in Serie A on Sunday.

Elsewhere, Napoli suffered a shock 1-0 home defeat to Chievo thanks to Maxi Lopez's strike, hosts Fiorentina were held to a scoreless draw by Genoa, Lazio routed Cesena 3-0 and Atalanta claimed a precious 2-1 win away at Cagliari.

Juventus and Roma top the fledgling table after respective wins over Udinese and Empoli on Saturday left last season's top two with maximum points.

Inter, who were held to a scoreless draw away at Torino last time out, moved up to third after a one-sided encounter at the San Siro.

Early last season Inter handed the 'Neroverdi', then in their maiden season in Italy's top flight, a 7-0 defeat.

Sassuolo, who only saved their top-flight status at the 11th hour last season, were expected to pose a bigger challenge this season having signed Algerian international Saphir Taider, from Inter, and seen striker Simone Zaza score on his competitive debut for Italy in a 2-0 win over Norway last week.

However, Eusebio di Francesco's men were trailing 1-0 after just three minutes when Icardi bundled home at the third attempt after being sent through by Mateo Kovacic.

Croatian midfielder Kovacic doubled Inter's lead when he ran on to Osvaldo's through ball to beat Andrea Consigli from close in on 21 minutes.

Icardi was unmarked when he made it three with a curling drive from outside the area on the half-hour and Inter went in for the break 4-0 to the good when Osvaldo tapped home the rebound from Consigli after Dodo's shot to the left of goal was blocked following good work down the left by the former Roma man.

Icardi secured his hat-trick eight minutes after the restart when he ran on to Kovacic's perfect through ball to whip it past a rooted Consigli.

Sassuolo's frustrations boiled over on the hour with forward Domenico Berardi red-carded for elbowing Juan Jesus.

Osvaldo added his second on 72 minutes with an easy tap-in from Fredy Guarin's low cross and Guarin grabbed his own two minutes later with a powerful finish.

Sampdoria won 2-0 at home to Torino thanks to goals from Manolo Gabbiadini and Stefano Okaka, while Napoli were whistled off by their own fans after their defeat to Chievo.

Later on Sunday Milan will look to make it two wins from two when they travel to Parma.