Inter Milan got the new year of to a stuttering start after mid-table Cagliari ended their eight-game winning streak with a 1-1 draw at the San Siro.
The Serie A leaders went into the game with a six-point lead over nearest rivals Juventus, but any hopes of extending or even maintaining that advantage seemed slim after Robert Acquafresca gave the 13th-placed visitors a shock lead after 65 minutes.
Zlatan Ibrahimovic levelled 12 minutes from time to preserve Inter's unbeaten home record this season, but Jose Mourinho's men never got into their stride in the game and could see their lead at the top cut to four points should Juve see off Siena tomorrow.
Meanwhile Genoa moved into a share of fourth place in Serie A after starting the year with a thumping 3-0 win over Torino.
Giuseppe Biava headed the Rossoblu ahead in the 18th minute and Bosko Jankovic added a second in the 48th minute.
A third header, this time from Thiago Motta five minutes from time, earned Genoa all three points and lifted them above Napoli in the table, level on points with Fiorentina.
Torino reacted positively after going two goals down, but were unable to get back into the game and remain just one point above the bottom three, who are all in action tomorrow.