San Francisco Frontiers - Kerley fires warning shot to rivals in world 100m

Kerley, who set a world lead of 9.76sec when winning the US trials on the same Hayward Field track o go eighth in the all-time fastest list, had a slick start and cruised through the line without seeming to break sweat.

If Kerley underlined his status as favourite for the blue riband event, three other Americans won their heats to raise the prospect of a third-ever cleansweep at the world championships.

Marvin Bracey won his heat in 10.05sec before Trayvon Bromell clocked a rapid 9.89sec, both sprinters basking in the partisan support.

Then came the turn of defending champion Christian Coleman, who missed the Tokyo Olympics after missing three doping tests.

Coleman eased up well before the line, clocking 10.08sec ahead of Olympic 200m champion Andre de Grasse of Canada, also a two-time Olympic 100m bronze medallist.

Jamaica will be represented in Saturday's semi-finals by Oblique Seville, who clocked a heat-winning 9.93sec, and 2011 world champion Yohan Blake.

Reigning Olympic champion Marcell Jacobs of Italy, a shock winner in Tokyo who has struggled with injury this season, advanced on the coattails of Seville.

Blake finished behind Botswana teenage sensation Letsile Tebogo, whose heat-winning time of 9.94sec was a new under-20 world record.

Japan's Abdul Hakim Sani Brown won the final heat in 9.98sec ahead of Kenya's Ferdinand Omanyala, who ran 9.77sec last September to go ninth on the all-time list.

It was a remarkable result for Omanyala, who only just managed to secure a last-minute visa to travel to the United States and took to the track only hours after touching down on US soil.

Saturday sees the semi-finals scheduled for 0100 GMT, with the final to be run at 0250 GMT.

D.Parker--SFF