Napoli could concede the Serie A title to Inter Milan as soon as next week after falling to a 2-0 home defeat at the hands of Lazio on Saturday.
With five matches remaining in their respective league seasons the reigning champions trail Inter by 12 points following a poor display in Naples.
Matteo Cancellieri's early tap-in set the tone at the Stadio Diego Armando Maradona, and Toma Basic made sure of a fine win for ninth-placed Lazio with another simple finish in the 57th minute.
Lazio's performance was a good sign for their Italian Cup semifinal against Atalanta, which is delicately poised at 2-2 ahead of Wednesday's second leg in Bergamo.
But it leaves Napoli counting the days until they officially concede the Scudetto, as if they fail to beat Cremonese and Inter win at Torino next weekend, the Scudetto will return north to Milan.
"We had 70 per cent of the possession but didn't have a single shot on target," said disappointed Napoli coach Antonio Conte, who was also tight-lipped about rumours of him taking over the national team.
Massimilano Allegri ruled himself out of the Italy job earlier on Saturday, and Napoli owner Aurelio De Laurentiis said in a recent interview with The Athletic he wants a quick decision on the matter from his coach.
"The less noise made about it the better it is for everyone, at least until the end of the season," added Conte.
Napoli could have even lost by more on Saturday as in the 31st minute Vanja Milinkovic-Savic got his hands to an uncharacteristically poor penalty from Mattia Zaccagni, who then smashed over the rebound after slipping to the deck.
That was the first time Zaccagni had failed to score from the penalty spot in Serie A but it made no difference to the final result.
Napoli's title defence might effectively be over but Champions League qualification is still on the cards thanks to an eight-point lead on fifth-placed Como and Roma who drew 1-1 with Atalanta.
CHAMPIONS LEAGUE HUNT
Roma are also off worse in the head-to-head record, which decides the positions of teams who finish the season level on points, with Napoli.
"We know we're not already in the Champions League, there are five matches left and we're not where we need to be yet," said Matteo Politano, who also apologised for a "horrible performance".
Roma also have had problems of their own in recent weeks, with open conflict between coach Gian Piero Gasperini and Claudio Ranieri, who is a senior advisor to the Friedkin family, the capital club's billionaire American owners.
Gasperini abandoned Friday's pre-match press conference on the verge of tears after speaking about Atalanta president Antonio Percassi, with whom Gasperini had a strong working relationship during his hugely successful nine years in Bergamo.
Italian media have widely report one of Gasperini or Ranieri will be out the door come the end of the season, hardly the ideal backdrop as Roma head into a key clash against Gasperini's old club.
Gasperini said his successes at Atalanta, which include winning the Europa League in 2024, were down to a "club which was in sync with the coach", a clear hint he didn't believe he has that at Roma.
Roma director Frederic Massara insisted there was no problem between the pair and on the pitch the players appear to be pushing in the same direction as Gasperini.
Mario Hermoso's superb volley just before half-time meant Roma and Atalanta shared the spoils from an entertaining draw which also gave Juventus the chance to take a big step to securing Champions League qualification.
Juve, in fourth, host Bologna on Sunday knowing a win will take them five points ahead of Como and Roma, with Atalanta already six points behind in seventh.