Mauro Icardi inspired a superb comeback win for Inter Milan as Juventus saw their perfect start to the new Serie A campaign shattered with a 2-1 loss at the San Siro on Sunday.
Stephan Lichtsteiner had given the champions a 66th-minute lead but Icardi drew Inter level almost immediately then set up the winner for Ivan Perisic 10 minutes later.
It was a stunning response from Inter after their midweek Europa League defeat to Hapoel Be'er Sheva, and was barely spoiled by a last-minute red card for Ever Banega.
Milan Badelj scored a controversial winner eight minutes from time to give Fiorentina their second straight league win and consign Roma to their first defeat of the new domestic season with a 1-0 triumph.
Badelj beat Roma keeper Wojciech Szczesny with a low drive from outside the box but his shot went through the legs of teammate Nikola Kalinic, who was one of three home players standing in an offside position.
Joe Hart kept a clean sheet on his home debut as Torino and Empoli shared the spoils in a dire 0-0 draw at the Stadio Olimpico di Torino.
After a forgettable debut during Torino's 2-1 defeat at Atalanta following his deadline-day loan move to Italy, the England international barely had a save to make as both sides failed to claim all three points.
Hart was not called into action until the 63rd minute, when he kept out Riccardo Saponara's strike from outside the box. The 29-year-old then had to be alert to palm Andres Tello's shot moments later.
Cesare Bovo could have won it for Torino late on but his shot sailed wide as Toro earned a point to remain 12th in Serie A while the visitors lie in 16th place.
Sassuolo maintained their promising early-season form to end Genoa's 100 percent record.
Second-half goals from Matteo Politano and Gregoire Defrel gave Sassuolo a 2-0 win and lifted them into third place behind Napoli and Juventus.
The game turned in Sassuolo's favour when Lucas Orban conceded a 58th-minute penalty, which Politano converted, and Defrel extended the home side's lead with a brilliant header eight minutes later.
Genoa's misery was completed when Portugal midfielder Miguel Veloso was sent off after receiving a second yellow card four minutes from time.
Fabrizio Cacciatore scored with virtually the last kick of the game to give Chievo a dramatic 2-1 victory at Udinese.
Colombian striker Duvan Zapata grabbed his first goal of the season after 25 minutes for the hosts from Emil Hallfredsson's inch-perfect cross.
But Cacciatore struck in the fifth minute of stoppage time as the Verona side completed a comeback sparked when Roberto Castro equalised with eight minutes remaining.
Marco Borriello continued his hot scoring streak as Cagliari claimed a first Serie A win of the season by beating Atalanta 3-0 at home.
Veteran striker Borriello accepted Joao Pedro's pass to give Cagliari an eighth-minute lead, before home defender Fabio Pisacane was penalised and Atalanta's summer signing Alberto Paloschi missed his third consecutive Serie A spot kick.
Atalanta were made to pay when Mauricio Isla set up Marco Sau 10 minutes after the restart before Borriello lashed home a 25-yard free kick.
Crotone claimed their first-ever Serie A point in a 1-1 home draw against Palermo. The result moved Crotone off the foot of the table with Pescara slipping to the bottom.
It could have been even better for the Serie A new boys after Marcello Trotta gave them a 24th-minute lead, the former Fulham forward making the most of a rebound falling kindly for him.
Diego Falcinelli also went close for Crotone in the first half, but Palermo secured a point through Ilija Nestorovski's stunning strike after 66 minutes following a lovely through ball from Haitam Aleesami.