Olympic champion Brianna McNeal was out of the world championships before they really started for her, disqualified for a false start in her 100 metres hurdles heat.
The American McNeal left the infield in tears after being shown the red card and then arguing briefly and in vain with race judges.
Tobi Amusan of Nigeria topped the heats with a personal best 12.48 seconds, the fastest time ever run in a first round.
Jamaican season leader Danielle Williams had 12.51, American World record holder Kendra Harrison 12.55, and European champion Elvira Herman of Belarus also moved on.
German defending and European champion Johannes Vetter needed just one massive throw of 89.35 metres to move into the men’s javelin final, far exceeding the 84m qualifying mark.
The medal events later Saturday are the women’s 1,500m, 5,000m and triple jump; the men’s marathon and shot put; plus the men’s and women’s 4x100m relays.