Simone Inzaghi was the first person to celebrate with Felipe Caicedo. As the Lazio striker wheeled towards the sideline, his manager came sprinting on to the pitch, the two men colliding in joyful release. Together, they had snatched a draw from the jaws of defeat against the champions of Italy, at the end of a difficult week.

It was Caicedo who scored the 95th-minute equaliser against Juventus, but Inzaghi deserved to be credited with an assist. He had physically redirected Adam Marusic as the wing-back prepared to take the throw-in that would launch Lazio’s final attack, shoving him to face up the pitch instead of looking for teammates further back.

As a result, Marusic found Joaquín Correa. The Argentinian slipped between two Juventus players, then rode challenges from two more before laying the ball off for Caicedo. He spun away from Leonardo Bonucci and picked out the bottom corner with what turned out to be the final kick of the game.

This is what Caicedo does. He has now scored five goals after the 90th minute of Lazio matches within the past 12 months. Up till now, they had all been winners. This felt close enough to a victory for side that was missing four starters, including Ciro Immobile – winner of last season’s European Golden Shoe.

His absence was confirmed less than 24 hours before kick-off: the latest twist in a coronavirus saga that is threatening to engulf the club. Immobile, along with Lucas Leiva and Thomas Strakosha, had tested positive for Covid-19, just one day after Lazio’s club doctor, Ivo Pulcini, told the news agency Ansa that the whole first-team group was negative.

The discrepancy appears to have stemmed from contradicting results provided by different testing facilities. Pulcini was relying on those from Futura Diagnostica – a laboratory in Avellino that Lazio have used ever since Italian football returned from lockdown this summer. The positive results came from Campus Bio-Medico in Rome.

Lazio’s testing regime had come under scrutiny after Immobile played, and scored, in the 4-3 win over Torino this month, despite missing Champions League games either side. He tested positive for Covid-19 before fixtures against Club Brugge and Zenit, according to Synlab – the laboratory used by Uefa – yet Futura Diagnostica diagnosed him as negative in-between, and then again afterwards.

His is not the only case to raise eyebrows. Lucas Leiva did not participate in Uefa’s testing before the Brugge game as Lazio had decided to leave him out of their traveling squad. He had been substituted out of the preceding match, against Bologna, in the 42nd minute, but there was no confirmation from the club of any injury. He then returned against Torino, before testing positive with Uefa ahead of the Zenit game.

These are matters of more than just sporting concern. Actions that actively encourage the spread of the virus can be considered as crimes in Italy. Federal authorities raided Lazio’s training facility at Formello on Saturday, as well as Futura Diagnostica’s labs, seizing information relating to swab tests taken by players and staff. According to Gazzetta dello Sport, they also sought details on communications made between the club and the local health authorities (ASL) in Rome.

The newspaper reported that Lazio are one of only two Serie A clubs, along with Spezia, who conduct their testing outside of their home region. One consequence is that they, rather than the laboratory, become legally responsible for updating the relevant ASL about any positive tests.

No charges have been brought against Lazio at this stage. The only individual formally under investigation by the prosecutor’s office is Massimiliano Taccone, president of the board of directors at Futura Diagnostica. Nevertheless, the story will hang over the club until further clarity emerges. The Italian Football Federation also opened their own sporting inquiry last week.

Lazio’s owner, Claudio Lotito has defended his club’s actions, reasserting that mandatory tests were taken and that they came back negative. Pressed during an interview with La Repubblica about reports that Immobile’s test had provided a more ambiguous result, with a possible positive on a specific gene, he responded with a crass analogy that seemed designed to muddy the waters.

“What does positive mean?” Lotito demanded. “Positive means contagious, no? Even in the vaginas of every woman in the world you find bacteria. But they are not all pathogens.”

Inzaghi also rejected suggestions of wrongdoing during his pre-game conference, insisting: “We are following the protocol to the letter”. On Sunday, he preferred to deflect questions about Covid instead, turning the focus back to his team’s performances this season.

Despite traveling without a host of starters for those games against Brugge and Zenit, Lazio remain unbeaten in their Champions League group. Against Juventus, they fell behind early to a Cristiano Ronaldo goal and looked outmatched at times – with the Portuguese also hitting the post late in the first-half – but never gave up the fight.

“I am very calm,” replied Inzaghi asked if he was worried his team could face a points deduction. “As a manager, I could not have done more than I have with 12 or 13 players at my disposal. This has been a difficult period, with plans A, B and C. In a moment like that, this match against Juve has been a great one.”

His was not the last word that we would hear on Covid-19 this weekend. As coronavirus cases continue to rise in Italy, health authorities in Rome and Florence sought to ban all players based in their regions from traveling to join up with their national teams this week.

It is unclear how effective those moves were. Lazio’s Sergej Milinkovic-Savic was reported to have arrived in Serbia before their Euro 2020 qualifying play-off against Scotland. Nevertheless, clubs in other regions were furious at the possibility that they could be adversely affected if other teams’ players were to get a week of extra rest at a time of extreme fixture congestion.

“This situation is unjust,” said Inter’s chief executive officer Beppe Marotta. “We are angry. We will call for an intervention from the minister for sport. Like this, championships will be altered.”