American Sydney McLaughlin produced one of the greatest track performances of all time on Friday by shattering her own 400 metres hurdles world record to win World Championships gold.

The Olympic champion charged home in 50.68 seconds, slashing 0.73 off her previous mark of 51.41 set at the same springy Hayward Field last month and becoming the first woman to run under 51 seconds in the event.

McLaughlin finished well clear of the Netherlands' Femke Bol (52.27) and U.S. compatriot Dalilah Muhammad (53.13).

McLaughlin leads the race by a huge margin. Photo: Reuters

"We knew warming up that it was going to be one of those days," McLaughlin said after winning her first individual World Championships title.

"I knew coming home that if I just kept my cadence and stayed on stride pattern, we could do it and it happened."

McLaughlin in action during the women's 400 metres hurdles final in Oregon. Photo: Reuters

It was the sixth time in three years that the world record has been broken, after Russian Yulia Pechonkina's mark had stood for 16 years.

"The level in the 400m hurdles is certainly improving," said McLaughlin. "We have a full group of girls that are willing to push our bodies to the next level and we are seeing times drop. It's really an exciting time to be in the event."

McLaughlin charged out of the blocks and by the 100 metres mark already had the lead over Muhammad, who had held the world record as recently as June 2021.

McLaughlin built a comfortable gap before the back turn and finished several metres clear of Bol and Muhammad, the home crowd in Eugene, Oregon, erupting as the 22-year-old powered to the line.

Bol, who took bronze in Tokyo, said McLaughlin's dominance made her question her own performance.

"She was so far in front at the end so I was always doubting if I really had a good race because it felt very good. And then I saw the sign and I was like: Wow," she said.

"This is just amazing and it means a lot that she also broke the 51s barrier."

Much of the hype heading into the final had focused on McLaughlin's rivalry with 2019 champion Muhammad but the 32-year-old was left disappointed after coming back from a mild hamstring injury earlier this year. 

"I'm having mixed emotions to be honest," she told reporters.

"I'm proud of the way we had this moment. I definitely want to keep this season going. I knew that at this race I wasn't quite at my best but I was hoping for the best."

It was the first world record broken at this year's World Championships, the first on U.S. soil, and a much-needed boost for the American women, who have excelled in the field events but had been shut out on the track.

McLaughlin's accomplishment sent shockwaves through the athletics world.

"She's just special," Allyson Felix, the most decorated woman in track, wrote on Twitter. "In a class of her own."

McLaughlin said she enjoyed pushing herself to new highs.

"It's very special to push boundaries for myself, focusing on the 10 hurdles and to be able to improve upon that, what else could I ask for?" she said.