American Justin Gatlin has set up the prospect of a final showdown in London with Usain Bolt after winning the 100m in the US World Championship trials.
Gatlin powered through in 9.95 seconds ahead of compatriot Christian Coleman, the fastest man in the world so far this year, who finished in 9.98.
Jamaica's Bolt has qualified for the World Championships in August via a wildcard and is then set to retire.
Yohan Blake ran his fastest time in five years in the Jamaican trials.
The 27-year-old, who is making his comeback following injury problems, won the 100m in 9.90. Asafa Powell, who has been nursing tendonitis, failed to report for the final after posting 10.15 in his semi-final.
Fellow Jamaican Elaine Thompson clocked her fastest time this year in the women's 100m, crossing the line in 10.71.
At the US trials in Sacramento, US Paralympian Blake Leeper raced in the men's able-bodied 400m, breaking Oscar Pistorius' Paralympic T43 record in the semi-final heat.
Leeper, 27, who was born without lower legs, finished in 45.25, beating the South African's time of 45.39 but it was not enough to see him through to Saturday's final.