With just over three minutes left on the clock, Kansas City Chiefs' 27-year-old running back Damien Williams scored a highly contested touchdown to put his team in the lead over the San Francisco 49ers in February's Super Bowl.
At the time, Williams' score, which was ruled admissible by a video review, looked like awful luck for the San Francisco team.
But snatching defeat from the jaws of victory had an accidental benefit for the 49ers' home city. It might even have saved lives.
The defeat meant no parade, and no parade meant that millions of people did not travel to the city to line the streets in early February to cheer on their heroes, potentially spreading coronavirus in the process.
"If the 49ers had won, we now know that there were active cases in Santa Clara and San Francisco at the time," says Dr Bob Wachter, of the department of medicine at the University of San Francisco.
"It's certainly not implausible that if you had a million people on the streets hugging each other and drinking beer, that could have set off a New York kind of thing."
Instead, San Francisco lost, and escaped that fate.
In New York City, more than 11,000 have died from coronavirus. In the San Francisco Bay area, which includes the city itself as well as surrounding areas, a total of 10 counties and eight million people, the figure is 245.
While the Mayor, London Breed, has attracted criticism for failing to move the city's homeless out of communal shelters before an outbreak infected almost 100 of them, so far San Francisco appears to have escaped the worst.
Wachter, whose daily Twitter updates have detailed his hospitals' and the city's response to the pandemic, did not expect this.
"I did not at all have any sense that I would be chronicling this incredible success story. It actually did not cross my mind. I thought I was going to be chronicling the apocalypse," he says.
Political leaders in the city and surrounding areas have been praised for responding decisively to the outbreak, enforcing a "shelter in place" order which required residents to stay at home other than for essentials from March 17, five days before New York, more than two weeks before Florida, Georgia and Mississippi.
San Francisco was also among the first places in the US to ask residents to wear masks in shops and public buildings, and more recently was one of the first cities to set up a dedicated contact tracing workforce.
There has also been a high level of adherence to the rules, and despite being locked down for longer, the city has not yet experienced the protests and unrest seen elsewhere in the US.
Part of the reason they acted so swiftly may be the legacy of a different public health crisis, the one surrounding HIV and Aids, which broke out in the early Eighties.
Wachter moved to San Francisco in 1983 as the epidemic was just hitting the city, and remembers treating patients the same age as him, in their 20s, who he knew had only a year or two to live.
"Those of us that were around then remember the feeling of fear and tragedy all around us," he says.
The centre of the US HIV outbreak, San Francisco was the exception to an American political establishment that failed for years to acknowledge or address the scale of the crisis.
Ronald Reagan, the then president, did not make a speech about the outbreak until 1987, after thousands had already died in his country.
The first person known to have the novel coronavirus when they died was killed by a heart attack "due to COVID-19 infection," autopsy results obtained by the San Francisco Chronicle show https://t.co/yRxHrejRRS
San Francisco pioneered a model which treated the social impacts of the disease as well as the illness itself, combining non-profits and outpatient clinics, who could care for patients in the community, with specialist inpatient wards, and teams including social workers, nutritionists and mental health experts.
There are parallels to today's epidemic, says Dr Paul Volberding, a leading HIV specialist who worked on San Francisco's response to the outbreak in the Eighties.
"What we did was really to build a trust between the medical, the political and the gay community, the people at highest risk," he says.
"The kind of trust that results in the public following the recommendations of the political leaders - in this case sheltering in place and social distancing - depends on the sense that the authorities can be counted to tell you what they know and what they don't know. And you can trust them."
There was still stigma, and parts of the local medical establishment still resisted efforts to research and treat the disease. But the San Francisco model ended up being copied around the world.
The legacy of that is a strong health department that is closer to the community and to the local politicians than in many other places, and a generation of medics who know what it is to fight a terrifying, mysterious disease.
A fascinating look at how San Francisco Mayor London Breed managed to guide her city through the coronavirus outbreak with a steadier hand and more confidence than many other American leaders.https://t.co/mf0iYcsPhL
Both Dr Anthony Fauci, who has been part of US President Donald Trump's press briefings, and Dr Grant Colfax, current head of the San Francisco department of public health, were on the front lines of the epidemic in the Eighties and Nineties.
Wachter, who trained with Colfax, said the experience taught them both that sometimes, things really are as awful as they seem.
"I think what it told us is that this might actually be as bad as people fear," he says. "It's an easier way to get through your day to say 'yeah, they're overstating it, it's not going to be that bad'. Having lived through Aids, it really was that bad."