Bahamian Shaunae Miller-Uibo's 400 metres Olympic title defence ended on Tuesday as she finished last in the repechage after struggling through the heat with an apparent injury.
The 30-year-old Miller-Uibo was on the hunt for a third straight gold but pulled up midway through her preliminary race on Monday and walked the remainder of the way.
The newly introduced repechage - which allows competitors who do not clinch spots in the semifinals to race again with a chance of moving on - offered her a path forward on Tuesday but Miller-Uibo could not find any of her usual power.
She crossed the finish in 53.50, nearly three seconds slower than winner Gabby Scott of Puerto Rico, weeks after media had reported that she would not run the individual race in Paris.
The semifinals are set for Wednesday, with the medal race taking place on Friday.