Juventus pounced on a costly blunder by Roma earlier on Sunday to close the gap on the Serie A leaders to just one point after turning on the style to rout fellow title challengers Napoli 3-0 in Turin.
League newcomers Sassuolo stunned Roma at the Olympic Stadium by levelling in second-half injury time for a 1-1 draw to leave Rudi Garcia's leaders with just a four-point lead ahead of the top-of-the-table clash in Turin.
It gave both sides incentive, but Juve seized on home advantage to produce a dominant display and claim their 10th win of the campaign to close the gap to one point.
Spain striker Fernando Llorente tapped home for Juve in the second minute in somewhat controversial fashion and from then on Napoli struggled to find any rhythm.
Napoli coach Rafael Benitez hinted that Llorente's early goal had shell-shocked his side, but admitted he could not argue with the Bianconeri's two other "quality" goals.
"When you concede a goal so quickly in this stadium, it's never easy to get back into the match," Benitez told Sky Sport Italia. "But in the second half Juve scored two quality goals."
Juve missed several clear chances but made the difference in six second-half minutes when Andrea Pirlo curled a free kick past Pepe Reina and Paul Pogba beat the keeper with a stunning volley from at least 20 metres out 10 minutes from the whistle.
Llorente admitted Roma's blunder had given Juve the extra spur.
"Seeing Roma draw earlier, we knew it was a big opportunity for us. Even though the race for the scudetto is long, winning against Napoli tonight became crucial," the Spaniard said.
Roma's draw and Napoli's second defeat of the season, following their reverse to Roma last month, could turn out to be one of the turning points of the season.
Inter Milan, 2-0 winners over Livorno on Saturday, remain in fourth just three points adrift of Napoli and with a one-point lead on Fiorentina after La Viola's shaky 2-1 home win over Sampdoria thanks to a double from Giuseppe Rossi.
Rossi gave Fiorentina an 11th minute lead from the penalty spot after Gaetano Berardi fouled Alberto Aquilani at a set piece and doubled La Viola's lead six minutes later with a stunning curling shot from the edge of the area which took his league-leading tally to 11 from 12 games.
Fiorentina, however, suffered a late scare when Manolo Gabbiadini reduced the arrears late on for Samp and Vincenzo Montella admitted: "We risked finishing with a 2-2 draw and it wouldn't have been the first time this season, but we were lucky."
Roma looked to be on their way to a six-point lead over Napoli and Juventus despite spurining a host of chances having taken a 19th minute lead when Alessandro Longhi turned inot his own net.
However the hosts were stunned at the death when Domenico Berardi smashed the ball high into Morgan De Sanctis's net as confusion reigned in the Roma area.
"That's what happens when you don't score the second goal," said Roma coach Rudi Garcia, who has enjoyed a stunning start to his first season in Serie A.
"But if we continue to play like we did today we will win other matches. We are still in first place."
Among several other draws on Sunday, Chievo secured a precious point while holding under-pressure AC Milan to a scoreless draw at home.
Milan, who had Riccardo Montolivo sent off late in the second half, moved up to 10th but Massimiliano Allegri's side are 19 points behind Roma and 15 off the first Champions League places.
Allegri and vice-president Adriano Galliani could face the sack, following reports that club vice-president Barbara Berlusconi, the daughter of owner Silvio Berlusconi, has demanded sweeping changes among the club's management structure.
Allegri, however, remained defiant.
"If the club wants to change coach, they'll inform me," said the Italian.