World record holder Wayde van Niekerk was disappointed in his 400m Olympic title defence as he missed out on the final at Olympic Stadium in Tokyo.
Running in lane eight, Van Niekerk started slow with a reaction time of 0.381 and then had to play catch-up in the third semi-final race.
Van Niekerk, who broke a 17-year world record whe he clinched gold at the 2016 Rio Games, lost his momentum in the final 100m and ended with a fifth-place finish in 45.14.
That placed him as the 12th fastest finisher, not high enough to see him into the eight-man final field.
Bahama's Steven Gardiner won the race in a season-best time of 44.14 and American Michael Norman finished second in 44.52.
Following the race, Van Niekerk didn't talk to the two journalists waiting in the mixed zone as he walked away in disappointment.
Team SA sent over a 20-second audio clip of Van Niekerk apologising to the journalists before recounting his disappointment.
"Very disappointed with the run. I expected way more from myself, but it didn't work out the way I wanted it to work out," said Van Niekerk.
"It is what it is and we move forward."
It was always going to be tough for the 29-year-old, who has struggled to recover from injury in the build-up to this year's rescheduled Games.
Van Niekerk has been plagued with multiple injuries since 2017 and only raced in a handful of events before arriving in Tokyo.
*Lynn Butler is in Tokyo covering the Olympic Games for Sport24