Having been lured out of retirement to rescue his beloved club, Ranieri now meets Antonio Conte's league leaders in this season's first Derby del Sole.
Match preview
Amid talk of widespread unrest and awful results, Roma's hierarchy decided to end the brief reign of Ivan Juric as international football intervened, with the Croatian coach having overseen four losses in his final five league matches.
Either side of a disappointing draw in the Europa League, the Giallorossi signed off for the break by twice losing 3-2 in Serie A - to Hellas Verona and Bologna - and that was enough to spark a search for someone else to take charge of an ailing institution.
Partly placating the club's furious fans, Rome-born coach Claudio Ranieri was persuaded to reverse his retirement from club management, after waving an emotional farewell once he had led Cagliari to top-flight safety last summer.
Only Luciano Spalletti and Rudi Garcia - both of whom have also managed Napoli, but to very different effect - can boast a higher win rate than Ranieri (56%) throughout Roma's entire top-flight history; however, he now returns to the Eternal City with confidence at a low ebb.
Employed in a caretaker role until the end of this season, when he is set to move upstairs, Ranieri inherits a team sitting 12th in the Serie A standings after winning just three league games so far.
They are also languishing in 20th place in the 36-team Europa League rankings, four points off a top-eight place that would guarantee their spot in the knockout rounds - to make matters worse, arch-rivals Lazio top the table.
Ahead of this week's trip down to Campania, the Giallorossi have also won none of their last nine away fixtures in Serie A stretching back to last season - and only Lecce, Venezia and Verona have gained fewer points on the road this term.
Labelled the Derby del Sole - 'Derby of the Sun' - due to the Mediterranean climates of Naples and Rome, Italy's two southern giants played out an absorbing 2-2 draw when they most recently met in April.
They may have picked up just one point from two encounters last term, but Napoli are unbeaten in six league games against Roma at Stadio Maradona - a run which dates back to 2018.
Though Antonio Conte's side still lead the standings, their advantage at the top was cut to one point just before the break, and five teams are stacked behind them in a potentially wide-open title race.
Scott McTominay scored the opening goal at San Siro last time out, but Hakan Calhanoglu later equalised for Inter Milan, before missing a penalty that could have resulted in back-to-back defeats for the 2022-23 champions.
After a streak of 21 home wins in Serie A, Conte had previously lost his last home match 3-0 to in-form Atalanta BC, and only once in his career has he ever recorded successive home defeats in the Italian top flight - that was way back in 2009, while in charge of Atalanta.
Sentiment will be in short supply, then, as he greets Ranieri on Sunday evening, with the Scudetto still firmly in Napoli's sights.
Napoli Serie A form:
W
W
W
W
L
D
Roma Serie A form:
D
L
L
W
L
L
Roma form (all competitions):
W
L
W
L
D
L
Team News
At best, Roma star Paulo Dybala is set for a place on the bench this weekend, as the mercurial forward continues to be hampered by muscular issues - Claudio Ranieri has spoken of taking a cautious approach with 'La Joya'.
Without Dybala, the Giallorossi's win-rate drops by 13%, but top scorer Artem Dovbyk should be able to start despite carrying a knee problem.
Alexis Saelemaekers has returned to team training following several weeks on the sidelines, but Dovbyk's deputy Eldor Shomurodov and Spanish centre-back Mario Hermoso are both ruled out by injury.
Meanwhile, Romelu Lukaku - who scored 21 times while on loan at Roma last season - has been directly involved in four goals from five league matches against Sunday's hosts and will lead Napoli's attacking trident.
Antonio Conte appears to have a fully fit squad at his disposal, so Stanislav Lobotka could replace Billy Gilmour in midfield, and ex-Roma man Leonardo Spinazzola can compete with Mathias Olivera to start at left back.
Napoli possible starting lineup:
Meret; Di Lorenzo, Rrahmani, Buongiorno, Olivera; Anguissa, Lobotka, McTominay; Politano, Lukaku, Kvaratskhelia
Roma possible starting lineup:
Svilar; Celik, Mancini, Ndicka, Angelino; Kone, Cristante; Soule, Pellegrini, El Shaarawy; Dovbyk
We say: Napoli 1-0 Roma
As Roma are in disarray, it might take Claudio Ranieri some time to turn things around; meanwhile, Napoli are already a well-oiled machine.