Sha'Carri Richardson faces off against Elaine Thompson-Herah in the Olympic 100m final that might have been at a star-studded Prefontaine Classic Diamond League meeting in Oregon on Saturday.
US sprinter Richardson was barred from the Tokyo Olympics after being given a 30-day suspension for testing positive for marijuana at the US trials at Eugene's Hayward Field in June, the venue for this weekend's Prefontaine.
It meant that the world of athletics was denied the chance to see the charismatic 21-year-old Richardson line up against the might of Jamaica's Thompson-Herah and Shelly-Ann Fraser-Pryce.
In Richardson's absence, Thompson-Herah stormed to the gold medal in Tokyo in an Olympic record 10.61sec, making her the fastest woman alive. Only the late Florence Griffith Joyner has run faster.
Thompson-Herah led a Jamaican sweep of the 100m podium in Tokyo, with Fraser-Pryce taking silver and Shericka Jackson the bronze.
All three medallists will be lining up against Richardson on Saturday in a high-class field which also includes Tokyo 100m finalists Marie-Josée Ta Lou of Ivory Coast, Switzerland's Mujinga Kambundji and the USA's Teahna Daniels.
While Richardson has raced against Fraser-Pryce twice before -- finishing ahead of the Jamaican on both occasions -- Saturday marks her first head-to-head with Thompson-Herah, who also successfully defended her Olympic 200m crown in Tokyo to complete an unprecedented "double-double".
In Tokyo, both Thompson-Herah and Fraser-Pryce coolly batted away questions about Richardson, offering curt "no comments" whenever the US sprinter's absence was raised by reporters.
Richardson, meanwhile, warmed up for Saturday's showdown this week by debuting a striking new hairstyle in a video on Instagram, swapping out her signature flame-haired locks for blue and platinum.
"August 21 and I'm not playing nice," Richardson captioned the post.
Richardson's agent, Renaldo Nehemiah, says his client is focused on simply "running a good race" rather than who she is racing.
"She will be focused on executing her race to the best of her ability regardless of who is in the race," Nehemiah told the Wall Street Journal this week.
While Saturday's 100m race could well be a tantalizing glimpse of what might have been in Tokyo, it could also turn out to be a sneak preview of next year's World Championships, which will be taking place at the same venue.
- Hassan, Mu will compete -
The women's 100m provides the most compelling storyline of the weekend, yet a field laced with talent should ensure numerous highlights elsewhere.
In the women's 5,000m on Friday, Dutch star Sifan Hassan is planning an assault on the world record in her first race since a historic Tokyo campaign, where she won both the 5,000m and 10,000m golds as well as a bronze in the 1,500m.
In the men's 100m, meanwhile, all nine starters have clocked personal bests of under 10 seconds.
Although Italy's newly minted 100m champion Lamont Marcell Jacobs is not in the field, the line-up includes the USA's Tokyo silver medallist Fred Kerley and Canada's Andre de Grasse, the 200m gold medallist in Japan.
The women's 800m, meanwhile, will see teenage star Athing Mu take a well-earned victory lap following her dazzling Olympic gold medal display in Tokyo.
The 19-year-old from New Jersey has taken the sport by storm this year, turning professional in June after a record-breaking debut collegiate season.
Mu, who also won gold in the 4x400m in Tokyo, faces a rematch of the Olympic 800m final, with Britain's silver medallist Keely Hodgkinson and bronze medalist Raevyn Rogers also entered.
Elsewhere, the Prefontaine's mile race sees a rematch of the Olympic 1,500-meter final, where Norway's Jakob Ingebrigtsen defeated Kenya's Timothy Cheruiyot for the first time to take the gold medal.