Felix, who has picked up 13 world championship medals across her dazzling, nearly two-decade-long career, said she was savoring the time she gets to compete in front of Camryn, before she retires.
"Initially I was so disappointed with everything getting postponed, and then I began seeing all of the silver linings," said Felix. "She's just so aware."
Already a star at age 21, Sha'Carri Richardson proved she was worth the hype as she recorded a blistering 10.84 in the 100m, the top time in the event, despite her shoe coming untied during the race.
"I’ll be sure to lace them and tuck them for the next rounds to come," said Richardson, who achieved a 24.1 mph (38.8 km/h) top speed during the sprint.
"To win the Olympics, I’m gonna say it could take a world record," she added. "There are so many phenomenal names that are predicted to be at the Olympic Games."
Elsewhere in the day's action, reigning world champion Donavan Brazier clinched his 800m heat in 1:45, as expected, and 2016 bronze medalist Jenny Simpson, 34, won her first-round heat in the 1,500m in 4:11.34, as she bids for a spot in her fourth Games.