A few seconds after 9.50pm local time (12:50 UTC) on Sunday (1 August), we will know the identity of the Tokyo 2020 men's Olympic 100m champion.
It will be a new name laying claim to the title of 'world's fastest man' with Usain Bolt, the winner of the last three Olympic titles, long retired, and Athens 2004 gold medallist Justin Gatlin failing to qualify for the U.S.
All the main contenders who are in Japan made it through the first round, although pre-event favourite Trayvon Bromell had to rely on a fastest losers' berth to reach the semi-finals after finishing out of the automatic qualifier spots in his heat.
Here's the rundown of the challengers for perhaps the most prestigious tag in men's sport.
Bromell had been favourite until round one shock
In June, the American clocked the two quickest times of 2021 so far - 9.77 in Miramar, Florida, and then 9.80 to win the U.S. Olympic Trials in Eugene, Oregon.
That 9.77 is the seventh fastest time in history.
Having bounced back from injury and mental health issues, there would be few more popular winners of the gold than the 26-year-old.
However, he was below par in the first round in Tokyo, struggling to pick up in the early stages and eventually finishing fourth in 10.05.
That time saw him through to the semi-finals, but he will need to improve markedly if he is to better his eighth place in the Rio 2016 final.
De Grasse brings Olympic medal experience
Since winning three medals at Rio 2016, including 100m bronze behind Bolt and Gatlin, Canadian sprinter Andre De Grasse has struggled with a succession of injuries.
He did return strongly at the 2019 World Championships, taking 100m bronze and 200m silver, just as he did in Rio.
The 26-year-old was supremely impressive on Saturday, looking to have plenty in reserve as he clocked the quickest heat time of 9.91.
Having already shown himself to be a man for the big occasion, De Grasse will fancy his chances of claiming his first global title.
Simbine aiming to finally reach major podium
The African and Commonwealth Games champion Akani Simbine was not at his best in the first round, having to work hard to get to the front in a time of 10.08.
Simbine will be hoping this is when he finally ends up on the podium having finished fifth in the Rio 2016 final, fifth at the 2017 World Championships in London, and fourth in Doha two years ago.
He should be in good form, having set a new African record of 9.84 earlier this month in Hungary.
A repeat of that would almost certainly see him win a medal, but he needs to put his best foot forward on Sunday.
USA hoping for Baker's best
With Christian Coleman suspended and Noah Lyles only qualifying at the U.S. Trials over 200m, the American team is relatively inexperienced in sprint terms.
Ronnie Baker has been on the scene for a number of years, missing out in the trials for Rio 2016 and the 2017 London World Championships before winning 60m bronze at the 2018 World Indoor Championships.
That year, he was the only man to beat Coleman over 100m - doing it twice - but the following year was wrecked by injuries which saw him fail to make the American team for Doha.
Now injury-free, he recorded a new personal best of 9.85 behind Bromell in the U.S. Olympic trials final.
While this is his first major global competition, he has been a fixture on the Diamond League in recent times and is in with a strong medal chance.
Kerley making the most of the switch from 400m to 100m
At the 2019 World Championships, Fred Kerley was one of the favourites for gold over 400m.
He eventually took bronze behind Steven Gardiner, and ran the lead-off leg as USA took gold in the men's 4x400m relay.
But this year has seen him switch to the 100m to great effect.
In April, he ran 9.91 which was the fastest time in the world this year at that point. And at the U.S. trials, he lowered his personal best to 9.86 in securing the third and final spot on the team.
His form in Europe in recent weeks has been a little disappointing, but 9.97 in the first round in Tokyo - behind de Grasse - is something he can definitely build on.
Jacobs could be top European hope for Italy
Born to an Italian mother in Texas, Marcell Jacobs is the potential wildcard in this men's 100m.
A former Italian long jump champion, Jacobs reached the semi-finals at the 2019 World Championships.
But he really announced himself to the world at March's European Indoors with 60m victory in a world-leading time of 6.47 which was also a national record.
He carried this form over to outdoors, setting a new Italian record of 9.95 in May.
That fell in the first round in Tokyo as Jacobs, looking totally at ease on his Olympic debut, crossed the line in 9.94.
He looks to carry Europe's biggest chance of claiming the men's 100m title since Barcelona 1992 when Great Britain's Linford Christie struck gold.