AC Milan edged a nine-goal thriller with Parma at the Stadio Tardini to join Juventus and Roma at the top of Serie A.
Atalanta fended off a late Cagliari comeback to record their first victory of the season with a 2-1 win in Sardinia.
Sassuolo and Cagliari shared the spoils in a 1-1 draw in their first Serie A match of the new season.
AC Milan beat Lazio 3-1 in Filippo Inzaghi's first Serie A game in charge, while Inter Milan's Nemanja Vidic saw red.
Leeds United have completed their 14th signing of the summer with the arrival of Dario Del Fabro at Elland Road.
Former Arsenal goalkeeper Manuel Almunia has been forced to retire from football due to a heart condition.