Kenyan Beatrice Chebet shattered the women's 10,000 metres world record at the Prefontaine Classic on Saturday, as Britain's Josh Kerr beat arch-rival Jakob Ingebrigtsen in the mile race at the Eugene Diamond League meet.
Chebet clocked 28 minutes 54.14 seconds, taking nearly seven seconds off the previous World record set by Ethiopian Letesenbet Gidey three years ago to qualify for the event at the Paris Olympics.
"The last lap just motivated me, especially when Gudaf dropped. Then I realized 'Oh, I am the best, so I can go,'" said Chebet, who had the fans on their feet at Hayward Field in Oregon as she cruised through the finish.
The men's mile served up the biggest drama of the day as Kerr faced Norwegian Ingebrigtsen for the first time since he stunned the Olympic champion to win the 1,500 metres World title in Budapest.
Kerr pulled away from the pack with 600 metres to go but had Ingebrigtsen hot on his heels through the final stretch.
Ingebrigtsen, twice World champion over 5,000 metres, tried to find another gear but could not get past Kerr, who crossed the line in a national record time of 3:45.34s.
Making his season debut after missing eight months due to an Achilles injury, Ingebrigtsen finished in 3:45.60s with American Yared Nuguse third.
"These guys I'm racing against are going to get better and better each month, and I need to do the same to try and stay ahead," said Kerr.
"I've got into this position because of hard work and determination and the right staff around me and I'm going to stick to doing that for the rest of the season."
With the US Olympic trials set for next month, World champion Sha'Carri Richardson underlined her claim as favorite for the women's 100 metres, exploding off the blocks to finish in 10.83s.
Saint Lucia's Julien Alfred finished a tenth of a second slower with Briton Dina Asher-Smith third in 10.98s.
"I feel like my performance reflects my training as well as my mindset and as well as my faith, continuing to understand who I am," said Richardson.
Richardson's Jamaican rival Elaine Thompson-Herah, who completed a second successive Olympic sprint double in Tokyo, finished last in 11.30.
American Christian Coleman held off a late challenge from Kenyan Ferdinand Omanyala to win the men's 100m in 9.95 seconds.
The 2019 world champion beat Omanyala by 0.03 seconds with American Brandon Hicklin third in 10.08.
"I feel like I'm in the best shape I've ever been in and I feel like now it's just mentally putting it all together and doing what I know I'm capable of on race day," said Coleman, who also won the 100m at the Xiamen Diamond League meet.
