Olympic champion and world record holder Wayde van Niekerk has been eliminated from the men's 400m at the Tokyo Games.
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He ran a 45.14 in the third of three semi-finals on Monday - out of lane 8 - to finish 5th.
Only the top two from each semi-final qualify automatically for the final, and Van Niekerk's time was also not fast enough to secure one of the other two slots.
He finished 12th fastest after the semis.
While Van Niekerk's pedigree has never been in doubt, a place in the final was not always guaranteed in the build-up to Tokyo given his ongoing struggles with injury.
In 2017, the 29-year-old suffered a devastating knee injury during an exhibition touch rugby match that some experts believed would threaten his career.
It has been a long road back to full health since, and given that absence of international competition along the way, there has been uncertainty surrounding how Van Niekerk would perform in Tokyo.
Running out of lane 8 at the Rio Olympics five years ago, Van Niekerk provided one of the great moments in South African sporting history when he clocked 43:03 to beat Michael Johnson's long-standing world record and claim gold for his country.
Kirani James - the 2012 Olympic champion and silver medallist in 2016 - ran a 43.88 in the first semi-final to be fastest heading into the final, which takes place at 14:00 on Thursday.
South Africa's 400m hurdler Wenda Nel, meanwhile, finished 7th in her semi-final in 56.35. She, too, will not progress to the final.