Zlatan Ibrahimovic and Maicon both scored Sunday to help Inter Milan beat 10-man Sampdoria 2-0 and extend its Serie A record winning streak to 14.
Ibrahimovic headed in Maicon's cross in the 37th minute for his 10th goal of the season, and then set up the defender, who doubled Inter's lead in the 75th.
Sampdoria played with 10 men for almost the entire game after Gennaro Delvecchio was sent off in the seventh for head-butting Inter defender Marco Materazzi.
"I don't tolerate that kind of behavior," Sampdoria coach Walter Novellino said. "(Delvecchio's) reaction was simply unjustifiable."
Inter leads the league with 57 points, 11 more than second-place AS Roma, which beat Siena 1-0. Palermo is third with 39 points.
"The championship isn't finished for us," Inter coach Roberto Mancini said. "We have a nice advantage but we play Roma on Sunday _ a team in form and dangerous."
Also, Filippo Inzaghi scored to help AC Milan beat Parma 1-0 and maintain its push for fourth place.
Milan, which started the season with an eight-point penalty from the Italian match-fixing scandal, is in ninth place with 27 points, three fewer than Lazio and Catania.
Despite Delvecchio's red card, Sampdoria pressed Inter and threatened through Fabio Quagliarella and Francesco Flachi. But the Nerazzurri never looked out of control and Sampdoria tired in the second half.
"Paradoxically, we found it difficult when they went a man down. But after (Maicon's) goal, the situation sorted itself out," Mancini said.
Adriano, who started alongside Ibrahimovic in Inter's attack, had a goal disallowed in the 18th for offsides. Hernan Crespo replaced the Brazil striker in the 68th.
Inter players wore black armbands in memory of Leopold Pirelli, the former chairman of Inter's main sponsor Pirelli & C. SpA, who died Wednesday.
Also Sunday, Takayuki Morimoto scored an 88th-minute equalizer to hand Catania a 1-1 draw with Atalanta; Luca Toni scored one and set up another as Fiorentina rallied to beat Livorno 2-1 in a Tuscan derby; Reggina beat Cagliari 2-0 to climb out of the relegation zone; Ascoli snatched a 2-1 victory over Messina on late goals by Michele Paolucci; and Empoli was held to a 0-0 draw at Chievo Verona.
On Saturday, Lazio beat Palermo 3-0 and Udinese beat Torino 3-2.
Inzaghi tapped in Andrea Pirlo's free kick in the 76th at San Siro for his 127th Serie A goal _ but only his second this season.
After scoring, Inzaghi pointed to his name printed on the back of his shirt, gesturing both to the crowd and to Milan's dugout.
"Inzaghi has had and will have his chances, but while I'm still coach of Milan, it'll be when I deem it," Ancelotti said.
Inzaghi has started infrequently this season and is likely to spend more time on the bench if Brazil striker Ronaldo makes his expected move to Milan from Real Madrid next week.
"I can only think about the contribution that I can make," Inzaghi said. "Why shouldn't I be (happy about Ronaldo's arrival)? He has something to offer Milan."
Massimo Oddo made his full debut for Milan in the No. 44 shirt after signing from Lazio on Wednesday. The Italy defender was Milan's best player, stifling Parma's attack and making a series of runs down the right channel.
"Oddo made an important contribution with so many crosses," Milan coach Carlo Ancelotti said. "He did well both in attack and defense."
Milan could have won by a larger margin but Alberto Gilardino, Inzaghi and Kaka struggled in front of goal.
"We deserved to win but we toiled a bit," Ancelotti said.
At Stadio Olimpico, Mirco Vucinic scored in the 62nd for his first goal for Roma, taking Francesco Tavano's through ball and shooting from a tight angle.
Vucinic made a rare start in place of the suspended Francesco Totti and became Roma's 12th different scorer this season.
"We did doubly well to win such a difficult game," Roma coach Luciano Spalletti said. "They are a solid team and they know how to create problems for their opponents."
Siena midfielder Tomas Locatelli was sent off just before the final whistle for striking Daniele De Rossi in the face while jumping for a ball. Replays suggested that the incident was unintentional.