A pair of late goals courtesy of Arturo Vidal and Claudio Marchisio handed Juventus a 2-0 win over Torino in the Turin derby on Sunday and kept the champions on track for a successful title defence.
Elsewhere, Fiorentina maintained their bid for a third place finish thanks to a 3-0 rout at Sampdoria although La Viola were pushed back down to fourth when Milan secured a come-from-behind 4-2 win over plucky Catania.
Earlier Sunday Pablo Osvaldo scored a hat-trick and Erik Lamela one goal as Roma trounced Siena 4-0 at the Olympic Stadium to move up to fifth, while Palermo moved out of the relegation zone thanks to a shock 1-0 win at home to Inter Milan.
Inter's 13th reverse of the season was compounded by an Achilles tendon injury suffered by captain Javier Zanetti, and left the Nerazzurri in seventh, eight points off Fiorentina, who occupy the third and last Champions League place.
Juventus started the day having seen their 11-point lead over Napoli reduced to eight after the southerners' win over Pescara in Saturday's late game.
And after a stubborn display from the hosts at a rain-hit Olympic Stadium, it took a sublime goal from Vidal four minutes from the final whistle to send Juve's bench into raptures.
Six minutes later Marchisio sealed Juve's 25th win of the campaign, which restored their 11-point lead on Napoli with just 12 points up for grabs in the remaining four games.
"Compliments to Torino because they made life difficult for us. But we wanted to win this game and we achieved that aim," said Juve coach Antonio Conte.
"Vidal and Marchisio's goals were crucial, now we only need one point to celebrate a second successive Scudetto with three games remaining: that would be extraordinary."
Torino were reduced to 10 men in the closing stages when Polish defender Kamil Glik saw red for a second bookable offence following a foul on Quagliarella, meaning he has been sent off in both derbies this season.
Francesco Totti, meanwhile, failed to score but set up Osvaldo for his first and Lamela two minutes later before laying on Argentine-born Italian Osvaldo's third.
After a mid-season lull, Roma are now up to fifth and in contention for a place in the Europa League.
Milan, meanwhile, suffered a scare by Catania before Giampaolo Pazzini came off the bench to inspire a 4-2 win at the San Siro, which gave the Rossoneri a one-point lead over Fiorentina in their duel for third place.
"We had to win this game," said Mario Balotelli, who slotted home a late penalty on his return from a two-match ban.
"We made stupid mistakes to concede two goals, and then Pazzini came on and scored a double. Hat's off to him."
After Balotelli, Kevin Prince Boateng and Stephan El Shaarawy spurned a number of early chances for the hosts, Catania took a shock lead when Nicola Legrottaglie rose above the home defence to head Francesco Lodi's free kick past Marco Amelia.
Milan, however, remained a constant threat and Boateng was unlucky when his snap shot from El Shaarawy's chest-down hit the crossbar, after the slightest of touches from goalkeeper Alberto Frison.
Frison then did well to fingertip Balotelli's fierce freekick from 25 metres to safety, but he could do little when Mathieu Flamini fired home Boateng's chest-down from close range on the stroke of half-time.
Milan resumed in positive fashion but were stunned when Gonzalo Bergessio gave Catania the lead after collecting a cross on the left and lobbing the onrushing Amelia.
Sensing the urgency, Milan coach Massimiliano Allegri replaced midfielder Alberto Nocerino with Pazzini.
Barely 10 minutes later Pazzini picked up the rebound from a speculative Balotelli shot to fire home and level for the hosts.
Three minutes after that El Shaarawy forced another save from the keeper which Pazzini slotted home to give the hosts the lead.
Balotelli put the match beyond all reach in injury time when he won a penalty on the edge of the area and left Frison with no chance.