Lifelong Roma fan Ranieri said after he was hired last week that he has "no time for mistakes" as he attempts to salvage something from a season which looks as good as over.
Roma head to Napoli in 12th, four points above the relegation zone after four defeats in five league matches under Ranieri's predecessor Ivan Juric, who was sacked following a home loss at the hands of Bologna before the international break.
But while a drop to Serie B is unlikely given the quality of the squad and Ranieri's experience, Roma are already 12 points away from the Champions League positions which are a key objective of the billionaire Friedkin family who own the club and have been the target of supporter ire.
Roma haven't qualified for Europe's elite club competition since 2018 and fans were outraged by the sacking of idol Daniele De Rossi in September, after he was given a three-year contract only a few months before.
Ranieri may have to do without the perennially injured Paulo Dybala, who trained on his own on Thursday, while Mats Hummels will have to wait for his first start after coming down with the flu.
After Napoli, the capital club travel to London to face Tottenham in the Europa League before taking on high-flying Atalanta, who are one of six sides currently contesting a crowded league title race.
Antonio Conte's Napoli are a point ahead of Atalanta, Fiorentina, reigning champions Inter Milan and Lazio, with Juventus a further point back in sixth.
Conte, with the help of a clutch of summer signings including ex-Roma striker Romelu Lukaku, has managed to stabilise a team that put in the worst Scudetto defence since the 1960s.
Midfield lynchpin Stanislav Lobotka will make his first start since early October, but Conte is sweating on the condition of Scott McTominay who picked up a foot injury on international duty with Scotland.
Juve meanwhile take on AC Milan -- who sit seventh but are eight points behind Napoli with a game in hand -- at the San Siro on Saturday evening with Timothy Weah set to take on the seven-time European champions on the same ground where his father once ruled the roost.
George Weah won the Ballon d'Or a few months after joining Milan from Paris Saint-Germain in 1995 and subsequently won two Serie A titles while scoring a host of memorable goals.
And with Dusan Vlahovic out with a thigh knock -- the latest in a long line of injuries for Juve -- Weah could yet start at centre-forward just as his dad did.
Promising 19-year-old forward Kenan Yildiz will return to the scene of his finest hour so far in a Juve jersey, after his late brace last month gave his team a remarkable 4-4 draw away to Inter.
Man to watch: Patrick Vieira
France and Arsenal icon Vieira has to get Genoa up and running quickly after being hired on Wednesday following the sacking of Alberto Gilardino, who struggled this season in difficult circumstances.
Genoa sit one place and point above the relegation zone ahead of their Sunday fixture at home to Cagliari after two wins so far this season and an injury crisis so bad they gave Mario Balotelli his last chance at the top level.
Gilardino, who got Genoa promoted last year, paid for those poor results but his job was made more difficult not just by a wave of injuries but the club selling his two best players -- Mateo Retegui and Albert Gudmundsson -- close to start of the season.
Fixtures (times GMT)
Saturday
Verona v Inter Milan (1400), AC Milan v Juventus (1700), Parma v Atalanta (1945)
Sunday
Genoa v Cagliari (1130), Como v Fiorentina, Torino v Monza (1400), Napoli v Roma (1700), Lazio v Bologna (1945)
Monday
Empoli v Udinese (1730), Venezia v Lecce (1945)
