World champion Noah Lyles cruised into the 200m semi-finals at the US Olympic track and field trials in Eugene on Friday but was upstaged by 17-year-old prodigy Erriyon Knighton during opening heats.
Lyles, who saw his hopes of a Olympic sprint double in Tokyo brought to an abrupt halt on Sunday when he finished seventh in the 100m final, looked much more comfortable back in his specialist event at Hayward Field.
But the 2019 World Championship gold medallist was forced to settle for second place in 20.19sec behind teenager Knighton, who raced over the finish line in 20.04sec.
Knighton's winning time broke Lyles' US high school record of 20.09sec, set at the US Olympic trials in Eugene five years ago.
Lyles said he had set out to qualify with a minimum of effort after exerting himself in the 100m earlier in the trials.
"Top two -- there's no reason for me to gas out," said Lyles, admitting he felt much more comfortable in the 200m than the 100m.
"It always feels natural when I come back to it," Lyles said.
"I don't have to stress too hard, I don't have to think too much. I don't have to worry about getting a good start or not. It's a comfortable feeling."
Knighton, meanwhile, said he had benefited from having Lyles outside him.
"I just wanted to qualify," Knighton said. "But I had the world champion behind me so I couldn't let off the gas too much."
- World-leading Thomas -
In the women's 200m semi-finals on Friday, rising women's star Gabby Thomas produced another world-leading time run to storm into Saturday's final.
The 24-year-old Harvard graduate, who had clocked the fastest time in the world this year in Thursday's opening heats with a time of 21.98sec, improved that mark to finish in 21.94sec.
"My expectations for myself have just gotten even higher," Thomas said. "When I get on the track I expect to run sub-22."
Six-time Olympic gold medallist Allyson Felix, who will appear in her fifth consecutive Olympics in Tokyo, also impressed, the 35-year-old finishing third fastest to make the final in 22.20sec.
In other heat action on Friday, world 110m hurdles champion Grant Holloway looked in superb form as he blasted to victory in 13.11sec, finishing well clear of his nearest rivals.
The final heat of the 110m hurdles saw controversy with the sprinters only getting out of the blocks at the fifth attempt after four false starts.
Similar problems dogged the first round of the women's 400m hurdles, which saw three false starts.
Sydney McLaughlin, the 2019 world championships silver medallist, said her knees had started bleeding on the sun-baked Hayward Field track after being forced back to the blocks so many times.
"It just goes to show that anything can happen and you have to be prepared for it," said McLaughlin, who impressed with a dominant opening victory in 54.07sec.
Olympic champion and world record holder Dalilah Muhammad, meanwhile, was equally comfortable in her heat, winning in 55.51sec to reach the semi-finals.
- Covid disruption -
Muhammad is working her way back after her off-season was disrupted when she caught Covid-19 earlier this year.
"It kind of set me back a little bit but I kind of got my fitness back right when I needed to," she said.
In the men's 400m hurdles, Olympic hopeful Rai Benjamin looked in ominous form as he won his opening heat in 48.61sec.
Benjamin, the fastest man in the world this year with a time of 47.13, went out quickly to build up a huge lead coming into the home straight, shutting it down with around 50m to go and virtually walking over the line.
"I jogged the last bit. I could have ran a lot faster," said Benjamin, who says he is not targeting Kevin Young's 29-year-old world record of 46.78sec this weekend.
"The WR isn't on my mind. I just want to make this team. That's my number one focus. I just want to make this team 100%," Benjamin said.
Meanwhile, in the women's 800m, teenage star Athing Mu gave another remarkably composed performance, wining her heat in 1min 59.31sec to advance to Sunday's final.