Napoli failed to turn up for their Serie A clash against Juventus in Turin on Sunday after a coronavirus row threw Italian football into chaos.
The match was abandoned 45 minutes after its scheduled 1845 GMT start time after Napoli did not travel to Juve's Allianz Stadium, and now Gennaro Gattuso's side risk forfeiting the game 3-0.
Juventus players were present for the third game of the season, along with referees and a handful of supporters under the rain.
But not the Neapolitans, who remained in isolation at home on the instructions of the regional health authorities of the Campania region which hosts the city of Naples, after midfielders Eljif Elmas and Piotr Zielinski both tested positive during the week.
Juventus president Andrea Agnelli told Sky Sport Italia: "(Napoli president Aurelio) De Laurentiis asked me to postpone the match, I replied that there are regulations to be respected."
"A 3-0 win? I always prefer to win on the field," Agnelli added.
Juventus had confirmed they would "take to the field" as scheduled despite two positive tests among their staff this week, with coach Andrea Pirlo and the squad arriving an hour before kick-off.
"We have protocols that are very clear," said Agnelli.
"The protocol was studied by the Federation with the government. It is a living document, the important thing is to have the spirit of sporting honesty, the cases will be dealt with and resolved from time to time."
Serie A had insisted that all the health protocols were in place for the match to safely go ahead "even in the event of positive tests".
It added that these measures are "applicable to the situation of Napoli, who have two positive players for Covid-19".
Napoli are the first team in Europe's five major leagues not to take to the pitch due to the coronavirus pandemic in a scheduled game.
- '13 healthy players' -
The club, meanwhile, moved to deny reports that coach Gennaro Gattuso had returned a positive test and said that another round of swabs would be carried out on Monday.
Zielinski and Elma's positive tests came after last weekend's a 6-0 thumping of Genoa, who have since recorded 22 positive cases that includes 17 players.
Serie A pointed out that other matches had gone ahead despite positive cases such as the game between Torino and Atalanta, AC Milan against Crotone and Napoli's hammering of Genoa.
The league said it had "a precise rule to be adopted in the event of multiple positives that can lead to the postponement of matches only upon the occurrence of certain conditions which, at the moment, do not apply to the case of Napoli."
Serie A are applying UEFA rules that say a match can take place as long as a side have 13 healthy players, including a goalkeeper.
The only possible exemption would be a club which has an active outbreak of Covid-19 with more than 10 new positive cases in a week.
In that case the club can request a postponement, but only once in the season, which was the case of Genoa's game this weekend against Torino.
Serie A insisted "that the system of rules in force must guarantee maximum health protection for the people involved, equal treatment between the various clubs, as well as respect for the principles of fair play."
But Napoli believe the health instructions of their regional authorities supersede Italy's sports health protocol.
The players may have to remain in self-isolation for two weeks at a hotel near the club's facilities, Italian media said on Sunday.
Napoli had won both their Serie A matches so far this season, while reigning champions Juventus had four points after two games as they chase 10 title in a row.