Botswanan athlete Isaac Makwala has qualified for the 200m World Championships final - after being forced to pull out of the heats through illness.
But the 30-year-old claimed his vomiting ahead of the 200m heats, held on Monday, had been a one-off, and disputed claims that he had been tested by a doctor.
It came as the IAAF tried to contain an outbreak of food poisoning among competitors which had developed over the weekend.
Makwala was granted a reprieve in the 200m on Wednesday, and qualified through the heats and the semi-finals, held just hours apart, to keep his gold medal hopes alive.
The Botswanan was forced to run alone during the heats on a wet evening at the London Stadium, clocking up a qualifying time of 20.2 seconds.
To the delight of the watching crowd, Makwala performed a round of press-ups immediately after crossing the finish line.
He then finished second in his semi-final race to round off a remarkable turnaround of events.
It exemplified his defiant attitude after ITV News witnessed him accuse the IAAF of trying to "sabotage" his tournament when he was initially barred from running.
Despite turning up at the London Stadium on Tuesday, the runner was led away by security who refused him entry.
And Makwala claimed that a Great British runner such as Sir Mo Farah would have been treated differently if he insisted he wasn't sick.
Public Health England confirmed that around 30 people staying in official World Championship hotels had reported illness since the weekend.
Of these two were confirmed as norovirus, leaving several athletes withdrawing from competitions.