Sprinter Akani Simbine steps onto the world championship track in London tonight searching for three-hundredths of a second to reach his dream.

That was the difference between his fifth place finish and the podium at the 2016 Rio Olympics.

Some of his more illustrious compatriots are also in action on the opening day of the global showpiece, like Caster Semenya (1500m heat), as well as the long-jump trio of Luvo Manyonga, Ruswahl Samaai and Zarck Visser.

Wayde van Niekerk is also entering the fray tomorrow in the 400m heats.

Simbine, with a 9.89 personal best, has the talent to contribute to the tally. He's broken the 10-second barrier on 15 occasions so far. But his season hit a speed wobble after a sensational start in which he dipped under 10 seconds six times between March and May, the last of them while beating Olympic silver and bronze medalists Justin Gatlin and Andre De Grasse en route to his maiden Diamond League crown in Qatar.

Simbine's dip in form came after moving to his training base in Gemona, Italy, while coach Werner Prinsloo stayed at home because of work commitments.

"I think it was a mental issue. It got to a point where I believed in myself but there was a point where there was a little bit of doubt and I let that come into play," admitted Simbine, who turns 24 next month. But that changed after Prinsloo joined him in Europe about three weeks ago.

Said Prinsloo: "Going through rounds suits him so much better than one-off races."

The 100m semifinals and final are tomorrow night.

"After Rio last year he knew what it took to get into the final so the obvious step after that would be to get the medal . that's what we're going for."

Simbine also competes in the 200m next week.