Milan, Italy: Tensions flared on the touchline as Fiorentina claimed a controversial 2-0 win over Atalanta on Sunday to move up to fourth in Serie A.
Elsewhere, Polish striker Krzysztof Piatek became the first Serie A debutant in 68 years to score eight goals in the opening six games when he hit a brace for Genoa in a 2-1 win over Frosinone.
Bergamo-based Atalanta travelled to Fiorentina's Artemio Franchi stadium desperate to end a five-game winless streak.
But their hopes were compouned just after the hour when referee Paolo Valeri pointed immediately to the penalty spot, refusing to consult the video assistant referee (VAR) despite Federico Chiesa going down easily from Rafael Toloi's challenge.
Jordan Veretout stepped up to slot past Pierluigi Gollini after 63 minutes, and Fiorentina cemented the win when Cristiano Biraghi doubled their lead in stoppage time.
At the final whistle, tensions boiled over with furious Atalanta coach Gian Piero Gasperini confronting Fiorentina counterpart Stefano Pioli before the pair were dragged apart.
"He shouted at me that the penalty was non-existent," said Pioli.
"They gave a penalty against us for a fingertip against Inter, so this time they gave one in our favour for light contact," added Pioli, whose side lost to Inter Milan midweek.
"We were tenacious, a little lucky."
Fiorentina have 13 points from seven games, eight behind leaders Juventus, with Atalanta now six games without a win and one point above the relegation zone.
Polish new boy Piatek scored a quick-fire first-half brace to bring his tally to eight goals in six appearances as Genoa, with a game in hand, moved up to sixth.
Piatek arrived from Cracovia this season and becomes the first Serie A debutant to score eight goals in the opening six games since Karl Aage Hansen for Atalanta in 1949-50.
He got his first after 33 minutes, adding a second three minutes later.
Camillo Ciano gave promoted Frosinone their first goal of the season when he transformed a penalty four minutes before the break.
Elsewhere, Torino got back winning ways with substititue Simone Zaza sealing a late winner against Chievo, who look destined for the drop next season as they sit bottom having had three points deducted for false accounting.
Federico Santander scored one and set up substitute Riccardo Orsolini as Bologna came from behind to beat Udinese 2-1.
Champions Juventus maintained their perfect start to the season on Saturday with a 3-1 win in their top-of-the-table clash with Napoli.
Roma beat Lazio 3-1 to move to eighth but 10 points off the lead.
Meanwhile, Gennaro Gattuso's AC Milan, struggling in 15th, face a difficult trip to third-placed Sassuolo on Sunday, who could move second behind Juventus with a win.