LOS ANGELES • Teenage sensation Erriyon Knighton stunned the men's 200m field at the US Olympic trials on Friday with the leading time of 20.04 seconds in the opening round , weeks after he toppled eight-time Olympic gold medallist Usain Bolt's junior record.

Knighton, 17, beat world champion Noah Lyles, who claimed a second-best 20.19 finish at Hayward Field in Eugene, Oregon, and broke the 23-year-old's US high school record of 20.09.

"That was my first time racing against him. I've watched tons of his races. I love to see it," said Lyles.

"It reminds me of myself coming out here in 2016. I want to see people taking that path."

Lyles, a favourite to win the event at the Tokyo Olympics, failed to make the cut in the 100m earlier in the trials.

Knighton - who told reporters he counted Bolt, Lyles and four-time Olympic gold medallist Michael Johnson among his inspirations - and Lyles competed in yesterday's semi-finals. The result was not available at press time.

"I saved something most definitely," said Knighton, who believes it could take a 19.8sec or 19.7sec to punch a ticket to Tokyo.

"You don't want to push to your full capacity but you want to make it through the rounds and make the top three, but you can't use all your energy in one race.

"I just wanted to qualify. But I had the world champion behind me, so I couldn't let off the gas too much."

In the other events on Friday, reigning Olympic champion Dalilah Muhammad cruised through the first round of the 400m hurdles, setting up a showdown with world silver medallist Sydney McLaughlin, as six-time gold medallist Allyson Felix reached the 200m final.

World record holder Muhammad looked relaxed as she seized an early lead and never let up under hot and sunny conditions, which reached 35 deg C, clinching her heat in 55.51sec to win by more than 1.5sec.

"I just wanted to get out, set the race up, set my rhythm up and just kind of do enough to just kind of make it home," said Muhammad, 31, the 2019 world champion.

She competed in yesterday's semi-finals against a strong field including McLaughlin, 21, who posted the event's fastest time of 54.07sec and is trained by Felix's coach, Bob Kersee.

Felix, 35, who had punched her ticket to Tokyo for a fifth Olympics in the 400m, finished second in her 200m semi-final heat in 22.20sec, earning a spot in today's final alongside Gabby Thomas, 24, who clocked a world-best 21.94sec.

Elsewhere, Mo Farah will not race for a third successive 10,000m gold medal in Tokyo after he again failed to make the qualifying time in the British Athletics Championships on Friday - his last realistic chance to do so.

Farah, 38, who also won double Olympic gold in the 5,000m, needed to clock 27min 28sec to make himself available for selection.

He had fallen 22sec short of that target in his last outing at the start of this month, when he was hampered by an ankle injury.

On Friday he was marginally faster with 27:47.04, but still almost 20sec adrift.

World champion Shelly-Ann Fraser-Pryce won the Jamaican women's 100m title, clocking 10.71sec to confirm her spot for the Olympics.

The 34-year-old, who earlier this month set a world-leading 10.63sec, shook off a semi-final loss to double Olympic sprint champion Elaine Thompson-Herah. It was a masterclass of sprinting, getting out to her customary bullet start and holding off a field that had six of eight women running under 11sec this year.

It was her fourth 100m national title and sixth overall.

REUTERS, AGENCE FRANCE-PRESSE