American sprinter Fred Kerley won the 100 metres at the Golden Spike meet in Ostrava in 9.96 seconds on Wednesday, seeing off 2004 Olympic champion and veteran compatriot Justin Gatlin.
Kerley posted a sub-10sec time in April when he clocked 9.91 seconds for the second fastest time so far this season, trailing Trayvon Bromell's world-leading mark by 0.03 seconds.
At Ostrava, Kerley beat 39-year-old Gatlin who clocked 10.08 and Canada's Andre de Grasse on 10.17.
"I feel like it was perfect, I can't complain. It was pretty good," Kerley said.
He added that in the run-up to the postponed Tokyo Olympics, he was "just gaging, listening to my training" for the time being.
Kerley also ran the 200 metres, finishing second behind fellow American Kenny Bednarek, who clocked 19.93.
Sha'Carri Richardson won the women's 200 metres in 22.35 after making waves earlier on Wednesday with a tweet from Ostrava that read "First & last time here, not impressed at all".
Uganda's Jacob Kiplimo set a world-leading time of 26min 33.93sec in the 10,000m, the seventh fastest race of all time.
"I did not expect such a time, I was hoping for something under 27," said Kiplimo.
"The seventh time in history is something I really did not even think about."
Kiplimo stayed almost 23sec behind the world record set last October by his compatriot Joshua Cheptegei, who won the unofficial 3,000-metre race in Ostrava.
Ethiopia's Getnet Wale set a new world-leading time of 8min 09.47sec in the 3,000 metres steeplechase.
World record holder Armand Duplantis won the pole vault with an effort of 5.90 metres, beating two-time world champion Sam Kendricks by five centimetres.
"I think of course I can jump higher than 5.90 but today I just never really got the rhythm and I just didn't really jump that well," the 21-year-old Swede told AFP.
But he put on a conciliatory tone when asked about the prospects for his Olympic debut.
"I have a lot of time for the Olympics. I think I'm in good shape right now," he said.
Burkina Faso's Fabrice Hugues Zango won the triple jump with a 17.20m effort, almost a metre behind his 18.07-metre indoor world record from earlier this year.
"There are some good things to take from this competition because I was able to fix my run up today so I think technically I get something," Zango said.
"So in the next competition with good weather, maybe more warm, I think that I will go further."
Having used the Golden Spike as an outdoor test, the top athletes will now move to Gateshead, England for Sunday's Diamond League opener in the run-up to the delayed Olympic Games, which are due to start on July 23.