Team GB superstar Dina Asher-Smith has failed to reach the women's 100 metre final at Tokyo 2020.
Asher-Smith won silver in the event at the World Championships two years ago but finished third in the first semi-final, leaving her with a nervous wait to discover if she could qualify as one of the two fastest losers.
But the 25-year-old's time of 11.05 was far off her best pace and it was not enough to progress to Saturday's final.
Meanwhile, teammate Daryll Neita finished third in the last semi-final but her time of 11 seconds flat was enough for her to reach the final as one of the two fastest losers.
Former GB gold-medalist Denise Lewis suspects Asher-Smith is "race light" having arrived at the Olympic Games after disrupted preparations.
"I think Dina is race-light. It feels to me like she thinks she's a bit ring rusty," Lewis told BBC Sport.
"She's not getting into her flow like we normally see her. She feeds off quick races, quick times - and she just doesn't have that unfortunately.
"Let's not make excuses, she might get through - but she will be bitterly disappointed with that execution of that race. We don't often see that from Dina."
"So, Dina had a great reaction to the gun but she should be ahead of [Ajla] Del Ponte on the other side of her because she is a better starter. She is ahead - but not as much as we would expect.
"Then the second part, that ability to continue to stride and pick up power that you need at the end of the race in order to maintain that momentum just wasn't there.
"Del Ponte was coming through and Dina was moving backwards. This is a problem."
Asher-Smith will hope to bounce back in the 200 metre event on Monday, having triumphed over that distance at the World Championships.
In the meantime, 24-year-old Neita will bid for Olympic glory in the 100 metre final.
Johnson added: "You're in a situation where you thinking who would you rather have in the final: Dina or Daryll?
"It's a difficult choice but obviously with Dina being a terrific athlete, world champion... but Daryll's got the momentum.
"A PB yesterday and holding her own in the semi-finals - that was a tight race for the finish - and that's where you want that championship experience to come through."