Many football matches were played behind closed doors in the early days of the coronavirus outbreak in Europe, but few went ahead with thousands of fans. The clash between Atalanta and Valencia has now been blamed for the massive spread of the disease in Italy and Spain.
Atalanta, who played there UEFA Champions League games at the San Siro this season, hosted Valencia in front of 44 000 fans on 19 February.
Many of them likely engaged with each other during celebrations as the hosts beat the LaLiga side 4-1 on the night, and the mayor of Bergamo, Giorgio Gori, has now stated his belief that the match played a huge role in the spread of the virus.
"The match was a biological bomb. At that time, we did not know what was happening," he told Marca.
"If the virus was already circulating, the 40 000 fans who went to San Siro were infected.
"No one knew that the virus was already circulating among us.
"Many watched the game in groups, and there were lots of contact (between fans) that night.
"The virus passed from one person to another."
Meanwhile, immunologist Francesco Le Foche has insisted it was "madness" that the game went ahead.
"It's probably that there were several major triggers and catalysts for the diffusion of the virus," he said, as quoted by talkSPORT.
"The Atalanta-Valencia game could very well have been one of them. It was the apex of collective euphoria in a unique football season for this club.
"A month has passed since that match, so the timing is pertinent.
"The aggregation of thousands of people, centimetres from each other, engaging in manifestations of euphoria like hugging, shouting, all of that could've favoured viral reciprocation.
"I have to imagine many didn't want to miss that game if they had tickets, even if they felt a slight fever.
"With hindsight, it was madness to play with a crowd present, but at the time things weren't clear enough. It'd be unthinkable now."
The second leg in Valencia also went ahead, but behind closed doors, and several players from both sides have since tested positive for the coronavirus.
Do you think the match between Atalanta and Valencia should have been played behind closed doors or even postponed? Have your say in the comments section below.