AC Milan, Juventus and Udinese all won on Sunday to put daylight between themselves and the pack in the Serie A title race.
Milan won 2-0 at Atalanta to remain level on points with Juve, who beat Lecce 1-0, but Udinese are just two points back after they thumped 10-man Cesena 4-1 earlier in the day.
Milan, who have a better goal difference than Juve, had what on paper looked the toughest task of the day but they were given a helping hand in the first half.
Brazilian forward Alexandre Pato collided with Thomas Manfredini as the pair chased a loose ball in the box, with both crumpling to the ground.
The referee pointed to the spot and Zlatan Ibrahimovic shot home, low to goalkeeper Andrea Consigli's right.
Pato struck the upright in the second half before Atalanta also hit the post as a corner was flicked on by Simone Tiribocchi, touched by Matias Schelotto and then German Denis at the back post from a yard out just failed to turn it inside the woodwork.
Kevin-Prince Boateng scored the clincher eight minutes from time after being set up by Ibrahimovic, knocking the ball in off the bar from six yards.
"It was an exciting and physical match, we knew that Atalanta could create problems," said Milan coach Massimiliano Allegri.
"The lads adapted straight away, we created a lot of chances and I'm satisfied with the performance."
At rock bottom Lecce, Juve won thanks to a horror error from home goalkeeper Massimiliano Benassi.
Mirko Vucinic's shot from outside the box didn't look too troublesome but Benassi failed to hold it and Alessandro Matri ran in to head home the rebound from barely two yards out.
"We're happy with the three points even though we could have put the game to bed sooner," said Juve coach Antonio Conte.
"We can definitely do better. I was afraid of Lecce but the defence held firm. We knew how to struggle against a team that made life difficult for us."
Udinese got off to a dream start with a goal on the counter-attack inside the first minute from Antonio Di Natale.
Cesena hit the bar on 39 minutes before Eder was fastest to react to the loose ball to poke home.
Udinese went back in front nine minutes into the second period and it was a goal that veteran goalkeeper Francesco Antonioli won't want to see again in a hurry.
Ghana international Kwadwo Asamoah, who will now head off to the Africa Cup of Nations, hit his shot from 20 yards with power but it went straight at the 42-year-old who somehow managed to allow past him.
Seven minutes later Maurizio Lauro was dismissed for a second booking and 15 minutes from time Romanian full-back Dusan Basta hit a stunning strike from distance that seemed to catch Antonioli by suprise as it dipped just inside the far post.
Late on Di Natale took a pass from Armero, turned smartly on the edge of the box and fired home into the top corner to add insult to injury.
Udinese are five points ahead of Lazio, who suffered a shock 4-0 defeat at Siena on Saturday, with Inter Milan, 5-0 winners over Parma, a point further back.
Napoli are two points behind Inter after continuing their rich goalscoring form - they ended 2011 with a 6-1 win over Genoa - by winning 3-1 at Palermo.
Goran Pandev, Edinson Cavani, against his former club, and Marek Hamsik scored for the visitors before Fabrizio Miccoli notched a late consolation.
Roma kept up their Champions League hunt as captain Francesco Totti scored for the first time this season, his two penalties earning a 2-0 win over Chievo.
Fiorentina lined up at Novara without a single recognised striker but that didn't stop them romping to a 3-0 win with Stevan Jovetic grabbing a brace, one from the spot, and Riccardo Montolivo scoring the other one.
Bologna beat Catania 2-0 to leave the bottom three six points adrift.