Justin Gatlin ran the fastest time this year to win the 100m at the Prefontaine Classic Diamond League meeting in Oregon in a wind-assisted 9.88 seconds.
Gatlin, 34, beat Jamaica's Asafa Powell - who ran 9.94 - with fellow American Tyson Gay third in 9.98.
Former Olympic champion Gatlin heads the Diamond League 100m standings having won in Shanghai earlier in May.
American Kendra Harrison won the 100m hurdles in 12.24 seconds, the second fastest time in history.
Britain's Tiffany Porter, 28, finished seventh.
Two-time Olympic 100m champion Shelly-Ann Fraser-Pryce, hampered by a toe injury, finished last in the 100m.
"I did not have any expectations," said Fraser-Pryce, who ran 11.18 seconds. "I'll just have to go back and assess the race. I prefer not to comment on the toe."
American Tori Bowie ran the fastest 200m of the year, 21.99 seconds, to beat Rio favourite Dafne Schippers, who clocked 22.11.
Great Britain's Laura Weightman came sixth in the women's 1500m.
Weightman, 24, clocked a time of four minutes 03.04 seconds in a race won by Kenya's Faith Kipyegon in 3:56.41.
In the women's high jump, Britain's Isobel Pooley, 23, finished eighth after clearing 1.88 metres.