While Juve's points deduction was overturned on appeal and they then progressed in the Europa League, their southern rivals slipped out of the Champions League and are enduring their first real downturn of an incredible campaign.
Match preview
After Italy's highest sporting court reversed a 15-point penalty handed down in January for financial misdemeanours, Juventus shot up from seventh to third in Serie A this week and could yet salvage a satisfactory conclusion to another sub-par season.
While the Bianconeri could still be punished at a later date, as a further FIGC (Italian Football Federation) hearing is set to be held, they remain in the running for silverware in both Europe and the Coppa Italia - plus a return to the Champions League for next term.
News of their reprieve came only hours before Juve's Europa League quarter-final decider versus Sporting on Thursday, and a 1-1 draw with the Portuguese champions secured both aggregate victory and a semi-final against competition specialists Sevilla.
In Lisbon, an early goal from Adrien Rabiot put Max Allegri's men in front, but the Frenchman then conceded the penalty which led to Sporting's equaliser and made for a more uncomfortable passage through to the final four.
Despite such a change of fortunes, Allegri will still reflect on his team's recent failures in Serie A, as they have lost both of their last two domestic fixtures and now aim to avoid posting a third straight league loss for the first time since 2011.
Beaten by Lazio and Sassuolo over the past fortnight, Juventus have recently lost the happy habit of securing no-frills 1-0 wins. Such a result would be welcome again on Sunday, and while they may have won just once in their last six league games against Napoli, they have also lost only one of the teams' last 12 meetings in Turin.
Napoli have suffered nine defeats during that spell, but a rampant 5-1 victory for the Azzurri in January's reverse fixture seemed to confirm a changing of the guard among the Serie A establishment.
The league's leading scorer and hot favourite to be crowned Capocannoniere come June, Victor Osimhen bagged a brace at Stadio Maradona that day to pull his side further clear at the top and dampen Juve's much-touted revival.
Yet his latest goal came in less joyous circumstances, as the striker's stoppage-time finish against Milan on Tuesday was not enough to stop Napoli exiting the Champions League and missing out on a first-ever semi-final; Khvicha Kvaratshkelia's penalty miss summing up both his night and the fortunes of his team.
While the wheels are hardly falling off Luciano Spalletti's well-oiled machine, his side have also failed to win three of their last six league games following a frustrating goalless draw with Hellas Verona last week - as many failures as during the first 24 fixtures of a spectacular season.
As a result, their long march towards a first Scudetto for 33 years has slowed ever so slightly, but they still enjoy a 14-point buffer from second-placed Lazio and will have no more 'distractions' from cup competition.
Aiming to do the double over Juventus for just the fourth time in their history - and the first since 2010 - they may now be tackling opponents with the most home points in Serie A this term, but Napoli have scored more away goals than anyone else and will surely have a point to prove on Sunday.
Juventus Serie A form:
L
W
W
W
L
L
Juventus form (all competitions):
W
D
L
W
L
D
Napoli Serie A form:
L
W
W
L
W
D
Napoli form (all competitions):
W
L
W
L
D
D
Team News
As Bremer sustained an injury on Thursday night, which caused the Brazilian defender to be withdrawn during the second half against Sporting, Juventus are set to bring Federico Gatti into their back line this weekend.
He should be joined by Bremer's compatriot Alex Sandro, who returns after serving a Serie A suspension last week, while Mattia De Sciglio may also be introduced by Max Allegri in order to give Juan Cuadrado a rest.
Angel Di Maria scored the only goal for Juve in their 5-1 thumping in Naples, but Arkadiusz Milik and Federico Chiesa are also pushing for selection in support of central striker Dusan Vlahovic; due to a flexor issue, Moise Kean is out of contention.
Counting the cost of their painful Champions League exit, Napoli will be without Mario Rui and Matteo Politano after both men were forced off by injury against Milan, while Giovanni Simeone's thigh problem keeps him sidelined too.
Amir Rrahmani hopes to overcome an ankle sprain, though, with Kim Min-jae and Andre-Frank Zambo Anguissa now ready to feature following suspension. Tanguy Ndombele served a one-match domestic ban last week and is also available.
In Politano's absence, Hirving Lozano should start on the right wing; Mathias Olivera comes in for Mario Rui at left-back.
Juventus possible starting lineup:
Szczesny; Danilo, Gatti, Sandro; De Sciglio, Fagioli, Locatelli, Rabiot, Kostic; Milik, Vlahovic
Napoli possible starting lineup:
Meret; Di Lorenzo, Kim, Jesus, Olivera; Anguissa, Lobotka, Zielinski; Lozano, Osimhen, Kvaratshkelia