An own goal plus a late score from Zlatan Ibrahimovic gave Serie A leader AC Milan a 2-0 win over Cesena on Sunday to open up a four-point gap in the standings.
Cesena's Maximiliano Pelligrino scored an own goal in first-half injury time, and Ibrahimovic doubled the lead just before the final whistle.
Milan should have won by a greater margin but Cesena's former Milan goalkeeper, Francesco Antonioli, made a number of crucial saves.
"I got a good pass and saw that the goalkeeper was out of position, and I just tried to keep my shot low," Ibrahimovic said. "We have to keep our rhythm up and keep going as we have been. What we did today gives us a slight advantage, but now we have to work to extend this lead."
Milan leads with 44 points. Napoli is next after a 2-0 win at Bari. AS Roma is third, six points behind the leader, and Lazio is fourth with 37.
Udinese rallied to beat Inter Milan 3-1, inflicting coach Leonardo's first loss and leaving the defending champions nine points behind its city rival in fifth place.
Dejan Stankovic gave the Inter the lead in the 16th minute and it appeared the visitor was in total control when he went close minutes later.
However, Udinese equalized soon after through Cristian Zapata and by halftime was leading 2-1 after Antonio Di Natale scored from a free kick.
In the second half, Maurizio Domizzi added a third after the defense was again unable to clear the danger, snapping Inter's run of five straight wins under Leonardo since the Brazilian took over from Rafa Benitez in December.
"We started the match well and with the right mentality," Leonardo said. "Unfortunately we couldn't come back, but it is a difficult stadium to come to and Udinese is in great form."
At Bari, Napoli forward Ezequiel Lavezzi diverted Edinson Cavani's free kick past goalkeeper Jean-Francois Gillet in the 38th minute.
Bari had to play the last 23 minutes with 10 men after Alessandro Parisi earned a second yellow card for elbowing Napoli defender Christian Maggio in the face.
Edinson Cavani wrapped up the win in the 87th with his 14th goal of the season.
Bologna, meanwhile, won 3-1 at home to Lazio.
Sergio Floccari gave the Rome side an early lead, but Gaston Ramirez and Marco Di Vaio put the hosts in the lead by halftime.
In the second half, Lazio did little to threaten and Di Vaio added his second goal of the game in stoppage time.
Both sides finished with 10 men. Henry Giminez was sent off for Bologna and Lazio's Andre Dias earned two yellow cards.
Also Sunday, it was; Chievo Verona 0, Genoa 0; Fiorentina 1, Lecce 1 and Sampdoria 0, Juventus 0.
At the San Siro, Cesena's Ezequiel Schelotto squandered a chance by shooting straight at goalkeeper Christian Abbiati in the 17th after Luca Antonini's weak back pass had put the striker through on goal.
Milan hit back, but was continually frustrated by Antonioli. First he stopped Robinho's shot after Zlatan Ibrahimovic had played the Brazilian through, then he twice denied Ibrahimovic.
Eventually Milan's pressure paid off. Antonio Cassano chipped over the defense and, as Ibrahimovic shaped to shoot, Pelligrino took the ball off the Swede's toes but sent it into his own net.
In the second half, Antonioli continued to frustrate Milan's strikers. In the 56th, he tipped Ibrahimovic's free kick over the bar, and in the 77th he raced off his line to smother Robinho's shot.
The Swede finally scored in injury time, blasting a low shot past Antonioli.
At Udinese, Inter nearly fell behind in the ninth minute when Maicon went close to lobbing his own goalkeeper Luca Castellazzi after he had miscued a cross by Giampiero Pinzi.
Stankovic's goal appeared to settle Inter's nerves. Thiago Motta laid the ball into his path, and Stankovic shot low into the far corner.
The Serb almost doubled his tally in the 19th. Udinese's defense failed to clear a corner and Stankovic hit a volley from the edge of the area that goalkeeper Samir Handanovic saw late and pushed over the bar.
Two minutes later, Udinese was level as Inter's defensive problems began to show. The ball wasn't cleared and from just inside the area Zapata shot past Castellazzi.
Di Natale then put Udinese into the lead when he curled a free kick over the wall.
After halftime, Udinese maintained the pressure and Di Natale and Domizzi went close to extending the host's lead.
Udinese scored a deserved third in the 69th. Inter's defense was unable to clear Di Natale's free kick, Zapata headed back into the box and Domizzi reached the ball first and flicked it past Castellazzi.
"Physically we are in good shape and playing well," Di Natale said. "It is always difficult against Inter, and it is a team that will be involved in the title race right till the end. That said, we are playing well and deserved to win today."
