Heavy snow made conditions difficult, but Roma fought back to snatch a thrilling 3-2 victory away to Atalanta with Vasilis Torosidis getting his debut goal.
Bologna completed a fantastic comeback to beat Fiorentina 2-1 with debutant Lazaros Christodoulopoulos.
An absolutely spectacular match saw seven goals, two red cards and a last-gasp Cagliari victory.
Milan dominated the first half, but Mario Balotelli was twice denied by Samir Handanovic, so Ezequiel Schelotto came off the bench to give Inter a 1-1 draw in the Derby della Madonnina.
Juventus swept Siena aside 3-0, Paul Pogba completing the rout, but the Tuscans did hit the woodwork twice.
Two wonderful strikes from Stefan Radu and Senad Lulic gave Lazio a 2-0 victory over Pescara.
Palermo saw Salvatore Aronica sent off and had more of the ball, but a Sebastien Frey wondersave earned Genoa a point.
Catania continue their march on European qualification after earning a shock 2-1 victory away to Parma.
Andrea Poli and Eder secured Sampdoria’s 2-0 victory over Chievo, but Cristian Puggioni somehow escaped a red card.