Champions Inter recorded their second goalless draw in a row at Fiorentina last night to leave Udinese and Napoli clear at the top of Serie A.
Forwards Alexis Sanchez and Fabio Quagliarella netted with superb strikes to give Udinese a 2-0 win at coach Pasquale Marino's former club Catania.
Fellow surprise pacesetters Napoli beat bottom side Reggina 3-0 thanks to a simple hat-trick from striker German Denis.
The pair have 20 points from nine games with stuttering Inter slipping from joint top to fourth on 18 after again failing to find the net following Sunday's 0-0 home draw with Genoa.
Inter coach Jose Mourinho left forwards Adriano and Julio Cruz out of his squad for the trip because of indiscipline but they still had enough firepower and chances to beat a weakened Fiorentina.
Winger Mancini hammered against the bar and later blasted over from a good position while Zlatan Ibrahimovic and Hernan Crespo had decent chances.
Mourinho's three-pronged attack again did not function properly, however, and the home side's own version also misfired without the suspended Alberto Gilardino and injured Adrian Mutu.
"Without doubt we have had three great chances to score," Mourinho told Sky.
"It is not easy to win here."
Milan moved above their city rivals into third, one behind the leaders, after a battling 2-1 home win over Siena.
Kaka's penalty after Filippo Inzaghi had been dragged back settled the game after Simone Vergassola had equalised Inzaghi's opener.
Juventus continued their resurgence by winning 2-1 at Bologna with winger Pavel Nedved scoring a neat first and then needing two deflections for his cross to sneak in at the near post for the second.
Juve, who were without Del Piero and a host of other injured players, now lie five points off the top.
Roma's home game with fellow strugglers Sampdoria was abandoned after six minutes because of torrential rain.
Under-pressure Roma coach Luciano Spalletti will at least be glad of the respite after a dreadful run of results with his side set to be fresher for Saturday's game at Juventus.