Isaac Makwala put a difficult 48 hours behind him by qualifying for Wednesday's IAAF World Championships 200 metres semi-finals via a time trial after being declared "medically fit" by the IAAF.
Running on his own inside London Stadium, Makwala - the world leader in the event having clocked 19.77 seconds in Madrid in July - recorded a time of 20.20secs to comfortably beat the qualifying time of 20.53s.
He signalled his confidence in his fitness to run by celebrating his progression to the semis with a series of press-ups.
The IAAF controversially withdrew the Botswanan from Monday's 200m heats and the 400m final the following day after he displayed symptoms similar to those affected by an outbreak of gastroenteritis at a team hotel.
World athletics' governing body cited a 48-hour isolation protocol recommended by Public Health England for Makwala's exclusion and he was given another chance to race following the conclusion of that period after a request from the Botswanan federation.
Makwala is expected to be the main challenger to Wayde van Niekerk's hopes of becoming just the second athlete to win the 200m and 400m at the same championships, with Michael Johnson the only person to have previously achieved the feat.