The Derby del Sole takes place with the hosts having lost to lowly Empoli and then seen Inter Milan take over as Italian champions; meanwhile, Roma are closing in on a return to the Champions League.
Match preview
After letting two points slip by drawing 2-2 with Frosinone less than a week earlier, Napoli came up short against another side struggling to stay afloat in Serie A last Saturday, failing to find a way past Empoli at Stadio Carlo Castellani.
Following that toothless 1-0 defeat, which marked a new low in their woeful defence of the title, interim coach Francesco Calzona has now won just three of his first nine league games, having become the Partenopei's third manager since Scudetto winner Luciano Spalletti departed last summer.
Not only are they lacking their former verve up front, Napoli have now conceded at least one goal in 12 consecutive top-flight matches, and only twice in club history have they recorded a longer streak without a clean sheet - most recently in 1998.
After Inter's success in Monday's Milan derby, they have relinquished their status as reigning champions, and as that burden seemed to weigh so heavily on their shoulders, perhaps they can face a tough run-in with more freedom.
Also set to tackle Bologna and Fiorentina before the end of the season, Napoli now host fellow European contenders Roma, having gone unbeaten through the teams' last five meetings at the Maradona.
However, they went down to nine men and were beaten 2-0 in December's reverse fixture, ending a run of seven straight matches without defeat to the Giallorossi.
After recording three big wins on the spin to reach the Europa League semi-finals and advance their cause in Italy's top-five race, Roma suffered a setback last weekend, losing 3-1 at home to fourth-placed Bologna, who are also vying for access to the Champions League.
While Serie A has earned five spots in the next edition of UEFA's top club competition, Daniele De Rossi's side could not afford to slip up again in midweek, with Atalanta BC just four points behind and having one game in hand.
On Wednesday evening, Roma played out the final 18 minutes of their match against Udinese, nearly two weeks after Evan Ndicka's collapse caused it to be suspended amid dramatic circumstances.
They restarted all-square at 1-1, but Bryan Cristante's stoppage-time header snatched maximum points in Udine, where the hosts were under new management, as De Rossi's former Italy teammate Fabio Cannavaro made his debut as Bianconeri boss.
Roma regularly take care of business against Serie A's lesser lights, but in games between clubs currently occupying the top eight places, they have collected the fewest points - a longstanding weakness that proved beyond both Paulo Fonseca and Jose Mourinho's ability to resolve.
Their tally of just eight from nine such contests this season is followed by Napoli's meagre total of 10, but at least one side will improve that metric on Sunday evening.
Napoli Serie A form:
D
D
L
W
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L
Napoli form (all competitions):
L
D
L
W
D
L
Roma Serie A form:
D
W
D
W
L
W
Roma form (all competitions):
D
W
W
W
L
W
Team News
As both Amir Rrahmani and Mario Rui are back in action after serving one-match bans, Napoli's defence should take a more familiar appearance this week, after Francesco Calzona was forced to improvise in Empoli.
Left-back Mathias Olivera is unlikely to win his race to return from a thigh injury, but the hosts should otherwise have a full squad to choose from.
Therefore, an attacking trident of Victor Osimhen, Khvicha Kvaratskhelia and Matteo Politano is set to start once again. The latter - who scored his first Serie A goal against Roma, nine years ago - has been directly involved in 13 top-flight strikes this season and needs just one more to match his best tally, set in 2017-18.
The visitors, meanwhile, will have half an eye on Thursday's Europa League showdown with new German champions Bayer Leverkusen, but Daniele De Rossi is not expected to rotate his squad too much.
Two changes from the side that lined up against Bologna are necessitated by suspensions for Diego Llorente and Leandro Paredes, while Chris Smalling and Romelu Lukaku are both injury doubts.
Evan Ndicka could return to the bench after recovering from the incident that saw Roma's game against Udinese halted, but as Smalling and Llorente are unavailable and the Ivorian will not start, Juventus loanee Dean Huijsen could deputise in central defence.
If Lukaku cannot lead the line, either Sardar Azmoun or Tammy Abraham will be supported by Stephan El Shaarawy - the latter has racked up five goals from his last six league visits to Naples.
Napoli possible starting lineup:
Meret; Di Lorenzo, Jesus, Rrahmani, Rui; Anguissa, Lobotka, Zielinski; Politano, Osimhen, Kvaratskhelia
Roma possible starting lineup:
Svilar; Karsdorp, Mancini, Huijsen, Angelino; Bove, Cristante, Pellegrini; Dybala, Abraham, El Shaarawy