Gonzalo Higuain hit his 24th goal in as many Serie A games as triumphant Napoli and Juventus moved closer towards a scudetto duel after slip-ups by title rivals Inter Milan and Fiorentina.
Higuain and Napoli have been transformed since Maurizio Sarri took over from Rafael Benitez last summer but it took a second-half penalty for the Argentinian to kept Napoli top of the pile in a cagey 1-0 win over 10-man Carpi.
Napoli’s 17th win of the campaign maintained their two-point cushion on champions Juventus, who saw Juan Cuadrado break the deadlock on 73 minutes and Paulo Dybala wrap up a patchy 2-0 win at the death away to league new boys Frosinone.
After Fiorentina saw their title hopes dented in a 1-1 draw at Bologna on Saturday, Inter had the chance to replace La Viola in third place and maintain their title charge with a win away to basement side Verona.
But Roberto Mancini’s men maintained their poor form in front of the opposition net before settling for a 3-3 draw.
It left Fiorentina third at 10 points behind Napoli and Inter in fourth at 11 off the pace and probably now requiring a miracle to realistically challenge for a first title since their treble-winning season of 2010.
Elsewhere, AC Milan had 16-year-old goalkeeper Gianluigi Donnarumma to thank for producing a string of fine saves in a 1-1 home draw with Udinese, who took a 17th minute lead at the San Siro through Pablo Armero.
French striker M’Baye Niang rescued the hosts with a well-taken second-half leveller after running on to Carlos Bacca’s precise through ball to beat Orestis Karnezis three minutes after the interval.
Milan remain sixth and although now 16 points off the pace the Rossoneri are only six behind Fiorentina in the first Champions League qualifying spot.
Napoli were expected to cruise past Carpi as the Azzurri maintain their impressive bid for a first title in 26 years, only to find their path to goal more difficult than anticipated.
Even more fans had filled the San Paolo stadium after answering calls by a supporters’ group to hold up masks of Kalidou Koulibaly after the club’s Senegal defender was the victim of monkey chants during a 2-0 win at Lazio in midweek.
But the league leaders struggled to find a way past visiting goalkeeper Vid Belec until late in the second half when Koulibaly was hauled to the turf by Fabio Daprela. Koulibaly had almost broken the deadlock on 55 minutes when he came galloping in at the back post to bundle wide from a corner, while Jose Callejon had the ball in the net only to be ruled offside.  
Moments later Higuain forced a great stop from Belec with a sweeping drive from outside the area and then Napoli were handed a break when Raffaele Bianco saw red for a second bookable offence.  
But Napoli struggled to make their advantage count and it took Daprela’s foul on Koulibaly for Napoli to break the deadlock, Higuain stepping up to hit the net for the sixth consecutive game.
At Frosinone, Juventus had seen several great chances go amiss before Cuadrado sent a crisp, first-time shot from Alex Sandro’s delivery into the hosts net on 73 minutes.
Dybala wrapped up the points at the death for Massimiliano Allegri’s men when he swept Alvaro Morata’s unselfish lay-off past Nicola Leali in the first minute of added-on time.
In the evening's late games, Atalanta host Empoli in a mid-table clash and Roma host Sampdoria looking for the win that would move them to within two points of Fiorentina and close the gap on Napoli to 12 points.