Inter Milan suffered their heaviest defeat of the season by losing 4-1 to Atalanta in Bergamo, days after drawing with Barcelona.
The home side took the lead through Hans Hateboer before Mauro Icardi's penalty brought Inter level.
Gianluca Mancini put Atalanta back in front before Berat Djimsiti put the hosts 3-1 ahead.
Inter midfielder Marcelo Brozovic was dismissed in the second minute of stoppage time before Alejandro Gomez curled in a superb fourth two minutes later.
Bologna came back from behind to draw 2-2 at Chievo.
Federico Santander opened the scoring for Bologna but a Riccardo Meggiorini spot-kick and Joel Obi effort put the hosts into a half-time lead.
Riccardo Orsolini ensured the spoils were shared as Chievo moved to zero points after they started the season on minus three due to a punishment for accounting irregularities.
Roma beat Sampdoria 4-1 at the Stadio Olimpico with Stephan El Shaarawy scoring a brace.
Juan Jesus, Patrik Schick and El Shaarawy's first put Roma into a comfortable 3-0 lead before former Giallorossi striker Gregoire Defrel pulled one back late on, with El Shaarawy netting his second in added time.
Sassuolo and Lazio played out a 1-1 draw at the Mapei Stadium.
Marco Parolo opened the scoring for Lazio in the eighth minute when he was the quickest to react to Luis Alberto's parried effort but Gianmarco Ferrari's header pulled Sassuolo levelled seven minutes later.
Empoli were 2-1 winners against Udinese, despite a late strike from Ignacio Pussetto.
Empoli led through goals either side of half-time from Miha Zajc and Francesco Caputo. Rodrigo De Paul missed a penalty for Udinese one minute before Pussetto's strike, but the visitors were unable to draw level.