Sixth-placed Roma's 4-0 thrashing of fifth-placed Inter Milan was the lone success for the leading teams. Leaders Juve were held 0-0 at home to lowly Siena, while second-placed Milan shared a goalless stalemate with seventh-placed Napoli.
Udinese, in third, and Lazio, fourth, both lost in a terrible day for the country's top teams, although it was not a great day for entertainment either with four scoreless stalemates. At the San Siro, Milan had Zlatan Ibrahimovic sent off for violent conduct but still came closest to winning.
Robinho wasted a glorious chance to give Milan the lead from Ibrahimovic's flick when he was through one-on-one with goalkeeper Morgan De Sanctis, but he screwed his effort wide of the upright.
Midway through the second half Ibrahimovic was shown his marching orders for petulantly and needlessly slapping Salvatore Aronica, who responded, almost comically, by slapping Antonio Nocerino, behind whom the big Swede had been standing when he launched the intital assault. Aronica, however, escaped punishment.
Playing against ten men, Napoli created a great chance when Ezequiel Lavezzi picked out Edinson Cavani at the back post but his header was woeful. But Milan suddenly proved more dangerous on the counter and Urby Emanuelson set up Robinho only for De Sanctis to deny the Brazilian.
Juve dominated throughout against Siena in Turin but it was the visitors who should have won it when Gianluigi Buffon made amends for spilling Reginaldo's shot by somehow keeping out Alessandro Gazzi's follow-up from five yards out. It may be a missed opportunity for the leaders but they still have a point advantage on Milan with a game in hand.
Roma rout Inter
Roma kept themselves in the UEFA Champions League hunt by hammering Inter Milan 4-0 at the Stadio Olimpico. It was a miserable return to the Italian capital for Inter coach Claudio Ranieri, who resigned from Roma a year ago.
His side have now picked up only one point from three games following a run of seven straight wins. Juan opened the scoring on 13 minutes with a towering header from a Francesco Totti corner.
Fabio Borini doubled the lead four minutes before the break as he ran onto Miralem Pjanic's flick, cut inside Walter Samuel and then shot through Julio Cesar's legs. And four minutes after the break he beat the offside trap to race onto Juan's through ball, held off Lucio and again shot home between Cesar's legs.
Bojan Krkic wrapped up the scoring, and a shambolic defensive performance from the visitors, a minute from time as the diminutive striker held off the attentions of three defenders on the edge of the box before firing home into the corner.
Udinese upset by Viola
Udinese held onto third spot despite losing 3-2 at Fiorentina. Emblematic captain Antonio Di Natale gave them a 14th-minute lead with a clever dinked finish that deceived goalkeeper Artur Boruc, although it looked like it was really a mishit.
But the hosts were level five minutes before the break after Mehdi Benatia, on his return from CAF Africa Cup of Nations duty with Morocco, handled a cross in the box and Stevan Jovetic despatched the resulting penalty.
The hosts went in front on 56 minutes as Mattia Cassani headed home Manuel Pasqual's cross. In a disastrous return for Benatia, he gave away another penalty for bringing down Jovetic, who converted his second spot-kick before Gabriel Torje scored Udinese's second in the last minute.
Genoa beat Lazio 3-2 in the day's early match to boost their own European qualification hopes while denting their visitors' prospects of securing a Champions League finish.