By completing her lap in 50 sec 68, the reigning Olympic champion subtracted more than seven tenths from her previous world record (51.41) at the end of this world final, becoming the first woman under 51 seconds in the 400m hurdles , at only 22 years old.

"She is unique," praised on Twitter the American icon on the verge of retirement Allyson Felix, the athlete with the most medals in history at the Worlds with 19 awards - and her training partner in Los Angeles.

"It's the best performance I've ever seen," enthused the double decathlon world champion (2009 and 2011) American Trey Hardee.

"It replaces (David) Rudisha's 800m in the Olympic final in London (in 2012). This is only the beginning for +Syd+."

McLaughlin seized the world record in June 2021, then owned by her compatriot Dalilah Muhammad, during the American selections for the Tokyo Games, in 51 sec 90.

Since then, from her Olympic coronation (51.46) to the first World Athletics Championships on American soil in history, via the US 2022 "trials" at the end of June (51.41), she has lowered it by more than a second .

Three of four in Eugene

The native of New Jersey definitely likes the mythical stadium of Eugene, at the other end of the United States: it is there that she has established three of her four world records.

How to measure its performance?

With this supersonic time, McLaughlin is now 90 hundredths of a second faster than the second fastest woman in the world over 400m hurdles (Muhammad in 51.58).

American Sydney Mclaughlin crosses the finish line well ahead of the 400m hurdles final at the World Athletics Championships in Eugene, United States, on July 22, 2022 Jewel SAMAD AFP

And she would have beaten two competitors in the 400 m flat final run a few minutes earlier!

"It's unreal", reacted without euphoria McLaughlin, crowned world champion for the first time in individual, after being silver medalist in 2019 in Doha.

"I was in a kind of + bubble +, I just had to apply what I learned in training, without even thinking about it. Just letting things happen. I always had an incredible relationship with the Hayward Field", said the one who is also reigning Olympic champion and outgoing world champion with the American women's 4x400m relay.

Cadet world record, junior world record: McLaughlin, from a family of runners - her brother Taylor was vice-world junior champion in the 400m hurdles in 2016 and her father Willie semi-finalist in the 400m at the US selections for the 1984 Olympics - swept away everything in his path from his young years before confirming at the highest level.

Coached by Bob Kersee

Appearing on the international scene at the Rio Games, a few days after her 17th birthday, she was stopped there in the semi-finals.

Her arrival in 2020 in the structure led by the famous Bob Kersee, ex-coach of his wife Jackie Joyner-Kersee and her fourth coach in five years, marks a turning point for this prodigy runner, also comfortable in the 200m, 400m m flat and 100 m hurdles (record in 12.65).

It was in this group based in Los Angeles that she joined her idol, Allyson Felix, whose brother Wes is none other than her agent.

How does she envisage the sequel after this capital performance?

"We discussed with Bobby (Kersee) the advisability of changing discipline. I don't know if that will happen. Why not try the 400 m flat or the 100 m hurdles?", she recalls.

"Bobby, who always has new ideas, also talks about doubling" 400m hurdles and another discipline, she adds.

Renaud Lavillenie clears a bar during pole vault qualifications at the World Athletics Championships in Eugene, United States, July 22, 2022 ANDREJ ISAKOVIC AFP

McLaughlin climbed on the highest step of the world podium on Saturday evening between the same athletes as at the Tokyo Games last summer, but Femke Bol and Muhammad swapped places: this time the Dutchwoman is the silver medalist (52.27) and the bronze American (53.13).

In the pole vault, the 30-year-old Renaud Lavillenie, 2012 Olympic champion but never crowned outdoor world champion, is the only one of the three French pole vaulters to have somehow pulled himself out of the qualifications.

See you in the final on Sunday, with the Swede Armand Duplantis as the big favourite.

© 2022 AFP