USA's Sydney Mclaughlin competes in the women's 4x400m relay final during the Tokyo 2020 Olympic Games at the Olympic Stadium in Tokyo on Aug 7, 2021. (JAVIER SORIANO / AFP)

EUGENE, Oregon - Sydney McLaughlin smashed yet another world record in the 400 meters hurdles at the US championships on Saturday, while Michael Norman won the men's 400 meters.

In her final national championship race, Allyson Felix, the most decorated woman in track history, finished sixth in the 400.

Olympic gold medallist McLaughlin never faced a serious challenge in the final at Eugene, Oregon's Hayward Field, breaking her own world record to win in 51.41 seconds before offering up a double-thumbs to the roaring fans. 

Norman won in a world-leading 43.56 seconds, with Champion Allison and Randolph Ross finishing second and third, respectively.

Olympic gold medallist Sydney McLaughlin never faced a serious challenge in the final at Eugene, Oregon's Hayward Field, breaking her own world record to win in 51.41 seconds before offering up a double-thumbs to the roaring fans.

"When the gun went off you could just kind of feel that everyone was elevating the performance," said Norman, a Tokyo relay gold medallist.

The top three finishers in Eugene, Oregon, who meet certain qualifying standards, and reigning global title-holders will compete at the world championships, which will be held in the United States for the first time from July 15 at the same track.

Nineteen-year-old collegiate champion Talitha Diggs overcame an experienced field to win the women's 400 meters final in 50.22 seconds, with Kendall Ellis finishing second to reach her third world championships and Lynna Irby taking third.

"It was a great field so I just wanted to make sure to maintain my form, encage my core and push," said Diggs.

ALSO READ: Tokyo 2020: McLaughlin breaks world record to win 400 hurdles

As Felix completed her final race at the national championships, the 11-time Olympic medallist summed up her emotions as gratitude, relief and "a little bit, sadness."

"I think a lot about what's next," the 36-year-old told reporters.

Her finish Saturday makes her a strong contender to be selected for a relay team to compete in what would be her 10th world championships. She told reporters she liked the mixed relay.

World record-holder Kendra Harrison clinched the 100 meters hurdles final in a world-leading 12.34 seconds, holding off Alaysha Johnson by a hundredth of a second with Alia Armstrong finishing third.

World record-holder Kendra Harrison clinched the 100 meters hurdles final in a world-leading 12.34 seconds, holding off Alaysha Johnson by a hundredth of a second with Alia Armstrong finishing third

Reigning champion Nia Ali did not run in the final after clinching her semi-final heat earlier in the day.

World champion Noah Lyles overcame a recent COVID-19 diagnosis to scorch the men's 200 meters preliminaries, while Tokyo bronze medallist Gabby Thomas and fan-favourite Sha'Carri Richardson advanced on the women's side.

Lyles was the fastest man in the 200 meters heats in 19.95 seconds, with 100 meters world champion Christian Coleman, 18-year-old sensation Erriyon Knighton and Tokyo silver medallist Kenny Bednarek winning their respective heats.

Lyles said COVID-19 kept him off the track from Monday through Saturday last week.

ALSO READ; Lyles wins sprint double, Brazier takes 600m at Szekesfehervar event

Canada's Andre de Grasse (left), US' Noah Lyles (center) and US' Fred Kerley compete during the men's 200m event during the IAAF Diamond League athletics Doha meeting at the Khalifa International stadium in the Qatar capital on May 13, 2022. (KARIM JAAFAR / AFP)

"From what I can see I haven't had too much concern - at the same time, me and my coach are taking this race by race. He says if anything is looking abnormal, we're pulling out," said Lyles, who also collected bronze in Tokyo.

Fred Kerley, who won the 100 meters final the night before, also advanced.

Thomas won her heat in 22.59, while Richardson, who had failed to advance in the 100 meters, finished a tenth of a second slower to reach to the semi-finals. 

World champion Noah Lyles overcame a recent COVID-19 diagnosis to scorch the men's 200 meters preliminaries, while Tokyo bronze medallist Gabby Thomas and fan-favourite Sha'Carri Richardson advanced on the women's side

National collegiate indoor champion Abby Steiner produced the fastest time in 22.14, while world silver medallist Brittany Brown also advanced to the semi-final.

Reigning world champion Grant Holloway and twice Olympian Devon Allen, who is juggling a career as a wide receiver in the National Football League (NFL) won their respective heats in the men's 110 meters hurdles opening round.

"That felt good. Just to come back and see what happens - I'm excited with everything," said Holloway, who took silver in Tokyo.

Allen, who put the track world on notice when he produced the third-fastest all-time performance in New York earlier this month, said he would "take it easy" with the gridiron for a bit.

World and Olympic silver medallist Rai Benjamin advanced to the men's 400 meters hurdles final in 47.93 seconds.

In the 1,500 meters, 24-year-old Sinclaire Johnson and Tokyo Olympians Cory McGee and Elle Purrier St. Pierre punched their tickets to the world championships.

Hometown hero Cooper Teare, who ran at the University of Oregon, led the men's side with Jonathan Davis and Josh Thompson also making the cut.

Tokyo Olympian Hillary Bor clinched the men's 3,000 meters steeplechase final, with 2017 worlds bronze medallist and Rio silver medallist Evan Jager finishing second and Benard Keter taking third.

READ MORE: Muhammad breaks world record in 400 hurdles

In the field event finals, Tokyo silver medallist Chris Nilsen won the men's pole vault with a 5.70-meter leap and Kara Winger won the women's javelin throw with 64.26 meters.

Keturah Orji won the women's triple jump with a meet record 14.79 meters and Daniel Haugh won the men's hammer throw with a personal-best 80.18 meters.