Napoli have indicated they intend to take legal action after their challenge against the 3-0 forfeit defeat to Juventus was rejected by the Italian Football Federation's (FIGC) court of appeal.
Gennaro Gattuso's men did not turn up for the game in Turin last month and were also docked a point by Lega Serie A for failing to fulfil their fixture obligations.
Napoli argued they were banned from travelling by local health authorities as Piotr Zielinski, Eljif Elmas and a staff member had tested positive for COVID-19.
Juventus themselves reported two positive cases among staff a day before the game but made clear they intended to play the match at the Allianz Stadium.
Andrea Pirlo named a starting XI but the game did not go ahead as scheduled because of Napoli's absence and was officially cancelled.
However, the FIGC ruled Napoli ignored the coronavirus protocols in place, which states a team must fulfil any fixture if they have 13 available players, including at least one goalkeeper.
The court ruled "Napoli's behaviour was effectively creating an alibi for themselves not to play", and they "deserve the sanction because it was not at all impossible for them to take part in the match."
The verdict also concluded that "Napoli's conduct in the days leading up to the match was already aimed towards not playing, with clear violation of the fundamental principles that sporting justice is based on, namely fairness, decency and probity."
In response to the appeal rejection, Napoli released a statement on their official website on Tuesday to confirm they will take the matter to the Collegio di Garanzia dello Sport - the highest Italian sports authority.
The statement added: "The club totally disagrees with the sentence, which casts unacceptable aspersions on the conduct of the club, ignoring very clear documentation in its favour and delegitimising the authority of the regional health associations.
"Napoli has always sought to defend the values of fairness and sporting merit, so in this case too we will follow every legal avenue to ensure justice for its conduct, which respected public health and asked that the pitch be the only judge to decide the result of a football match."
The FIGC also upheld the league's decision to punish Roma with a 3-0 loss for fielding an ineligible player against Hellas Verona in their opening game of 2020-21.
Roma were found to have registered Amadou Diawara as an Under-23 player in their squad list when the midfielder had already turned 23.
The game at the Marc'Antonio Bentegodi finished goalless but Roma returned to zero points for the season following their sanction.
The Giallorossi also had their appeal rejected on Tuesday and CEO Guido Fienga told ANSA: "With all due respect, I cannot help but express my unhappiness at a sentence that I consider to be profoundly unjust.
"We have all missed an opportunity to intervene and modify an evident loophole in the rules, but above all there was no desire to avoid a punishment that is clearly disproportionate to the situation.
"We did everything we could by proposing a course of action in the appeal that would allow for equity on this rule, which currently does not recognise whether an error was in good faith or not."