Reigning Olympic champion Elaine Thompson-Herah won the women's 100m in 10.79 seconds at the Eugene Diamond League meeting on Saturday, holding off rising US star Sha'Carri Richardson on the same track that will host the athletics World Championships in July.
Jamaica's Thompson-Herah, who completed back-to-back 100m-200m Olympic doubles in 2016 and last year in Tokyo, made a smooth start on a rain-slick track at Hayward Field, took control at the 50m mark and powered to the win.
Thompson-Herah was satisfied with the victory, even though she couldn't match the world-leading 10.67 posted by compatriot Shelly-Ann Fraser-Pryce earlier this month.
"I'm excited I crossed the line healthy," Thompson-Herah said. "I don't care about the time. The rain was falling. It was a little cold.
"It shows I'm on a great path," added the Jamaican star, who pulled out of the Birmingham Diamond League event last week with a shoulder injury, testing herself in a lower-level meeting in Kingston last Saturday instead.
"I'm getting into shape," Thompson-Herah said. "I'm getting where I need to be."
Richardson won a close battle for second ahead of Jamaica's Shericka Jackson, both credited with a time of 10.92.
Richardson, 22, shot to prominence last season at the US Olympic trials with a wind-aided 10.64 in the final. But she missed the Tokyo Games after a positive test for marijuana.
Brazil's Alison dos Santos continued his strong start to the season, winning the men's 400m hurdles in 47.23. Despite the damp conditions he shaved one-hundredth of a second off the world-leading time he posted in winning at the Doha Diamond League event earlier this month.
The Tokyo Olympics bronze medallist said it was "amazing" to get a chance to test the World Championships venue.
"It's so nice, because you can feel the energy, you can feel the track, you can feel everything before the championships."
American's Khallifah Rosser was second and compatriot Quincy Hall third, both in 48.10.