AC Milan had Zlatan Ibrahimovic sent off as they were held to a shock 1-1 draw at home to basement boys Bari at the San Siro.
Gergely Rudolf put the visitors in front against the run of play in the 39th minute and they spent the rest of the game defending their lead.
Milan were struggling to find a way through, despite dominating possession and twice having goals ruled out, and Ibrahimovic let the frustration get the better of him as he was red carded in the 73rd minute. But Antonio Cassano saved Milan's blushes with an equaliser in the 82nd minute to take Milan five points clear of second-placed Inter at the top of Serie A.
Milan were looking to take advantage of city rivals Inter's 1-1 draw against Brescia on Friday night and bounce back from the disappointment of going out of the Champions League in midweek.
Roma revived their top-four ambitions with a Francesco Totti brace sealing a 2-0 victory over nine-man Lazio at the Stadio Olimpico.
Totti opened the scoring in the 70th minute before the Roma captain added his second from the penalty spot with seconds remaining. Lazio ended the game without both Stefan Radu and Christian Ledesma both shown red cards in the final stages of a heated encounter.
The result dropped Lazio to fifth place, with Roma one place and two points behind them.
Napoli returned to winning ways and rejoined the race for the Scudetto thanks to a 3-1 win over Parma.
Raffaele Palladino gave the home side a deserved lead in the 29th minute, but Napoli recovered in the second half with Ezequiel Lavezzi creating the equaliser for Marek Hamsik before putting Napoli ahead in the 56th minute.
Daniele Galloppa was given his marching orders for a dangerous foul on Hamsik in the 59th minute and Christian Maggio sealed the win for Napoli three minutes from time.
Udinese kept their hopes of Champions League football alive with four goals in 14 minutes to see off Cagliari 4-0 at the Stadio Sant'Elia.
Despite plenty of the chances on goal, the first goal of the afternoon came after 42 minutes through Mehdi Benatia. Two minutes later Alexis Sanchez doubled the lead with a memorable solo goal and then Antonio Di Natale notched twice in six minutes after half-time.
Fiorentina's late run into European contention continued after Juan Manuel Vargas scored the only goal at Chievo.
Vargas fired home a 25-yard free-kick three minutes into the second half. Sinisa Mihajlovic's men deserved the three points although the hosts came close to an equaliser in the final minute when only a fantastic save from visiting goalkeeper Artur Boruc prevented his Chievo counterpart Stefano Sorrentino from dramatically heading home.
A goal 13 minutes from time from Antonio Floro Flores gave Genoa a 1-0 victory over Palermo and boosted their slim hopes of playing in Europe next season.
Floro Flores struck towards the end of a game which had looked to be heading for a stalemate. The win lifts Genoa to within two points of Palermo, who have lost both of their matches under their new coach Serse Cosmi.
Bologna took a giant step towards defending their status with a narrow 1-0 victory at Lecce. Gaston Ramirez struck the only goal of the game in the 33rd minute to hand Bologna their 11th victory this season. Lecce were unlucky not to equalise before half-time when Daniele Corvia's strike struck the post.
Ten-man Sampdoria battled manfully at Catania but in the end could not prevent new manager Alberto Cavasin's reign beginning with a 1-0 defeat.
Cavasin, appointed earlier this week to replace the sacked Domenico Di Carlo, must have wondered what he had let himself in for when Fernando Tissone was sent off after 23 minutes. His new charges then held out until 15 minutes from time, when substitute Cristian Llama finally broke their resistance.
The defeat was Samp's third in a row and left them with just one victory in their last 11 matches.