Michael Norman fired another World Championships warning shot on Saturday, posting a world-leading 43.56sec to win the 400m at the US trials and put Tokyo disappointment further behind him.

Almost two months after winning the 400m at the Eugene Diamond League meeting in a meet record of 43.60, Norman returned to Hayward Field -- venue for next months World Championships -- and ran even faster.

"I'm kind of looking forward to going back to LA and fine-tuning this race and being even more prepared when Worlds comes around," the 24-year-old warned.

Norman insisted that his defeat at the Tokyo Games, where he went in as a gold medal favorite and faded to finish fifth with a time nearly a second outside his career best, was no longer a motivator for him even though it was devastating at the time.

"I'm just not really focusing on the past, more just moving forward and focusing on what I can control this year," he said.

Regrouping has meant going "back to the basics" he said, starting the 2022 season "with a very straightforward, straight-line mindset."

He's had a setback or two, including a back injury that cost him some training time.

But he's still been making steady progress on the track, his time in May shattering Michael Johnson's 22-year-old meet record.

Now he's gone faster, but Norman said the time was immaterial.

"It's just a number," he said. "It doesn't matter until world championships comes around the corner."

That may be so, but it's perhaps no coincidence that he's turned in two outstanding performances at Hayward Field, a beloved athletics venue in the United States which will see America host the outdoor Worlds for the first time.

It's another reason for Norman's rivals to beware.

"I guess I have a pretty good history at Eugene," he said. "I think I'll have a slight advantage."