Richardson, Omanyala storm to victory in Nairobi
Already the fastest woman in the world this year in the 100m, the 23-year-old American obliterated the field to win in a new meet time of 22.07 seconds.
Her victory in the 200m came a week after she won the 100m in a world-leading 10.76 seconds at the season-opening Diamond League meeting in Doha.
"The race was amazing. I came here to Kenya knowing that I have no excuse but to do my best," an elated Richardson said.
"I know I have more to do for my fans, for my loved ones."
It was her first victory in the 200m this year after finishing second in the Botswana Grand Prix, the second leg of the World Athletics Continental Gold Tour in Gaborone on April 29.
With her Jamaican sprint rival Shelly-Ann Fraser-Pryce pulling out of the Nairobi event after suffering a knee injury on Thursday, Richardson was the star attraction at her maiden appearance in Kenya.
Omanyala also thrilled the home crowd as he beat off rivals including second-placed Kenny Bednarek of the USA in a time of 9.84, the best in the world this season.
But he failed to top his African record of 9.77 seconds set at the same event in 2021, and the 27-year-old Kenyan said he had hoped for a better performance.
"I expected a better time, but it's a win and a world lead and I am happy about it," Omanyala told reporters.
Bednarek was second in 9.98 seconds with compatriot Marvin Bracy-Williams third in 10.03.