Two years after her emotional Tokyo Olympics exit, US superstar Simone Biles made a spectacular and dramatic return to international gymnastics at the world championships on Sunday in a "once in a lifetime" performance.

The 26-year-old successfully became the first female gymnast to execute a "Yurchenko double pike vault" now renamed "Biles II" during women's qualifying.

Her ambitious return earned her 15.266 points, far ahead of the competition.

In total, she accumulated 58.865 points at the end of the four apparatuses and took the lead in qualifying.

A 19-time world and four-time Olympic champion, Biles arrived in Japan for the 2021 Olympics as the huge favourite thanks to her four titles won five years earlier in Rio.

However, she broke down in full view of a global audience, withdrawing from most of the events.

She then explained that she was fighting against "twisties", a temporary mental block whereby gymnasts lose their sense of where they are in the air, with the risk of injury when they land.

She returned to action at the beginning of August and demonstrated that she had lost none of her incredible skills.

She won the US Classic, where she obtained the best scores on vault, floor and beam, followed by a record eighth US all-around title at the national championships.

"I think what success means to me is a little bit different than before because before everyone defined success for me, even if I had my own narrative that I wanted," Biles told Olympics.com prior to the world championships.

"So, now, it's just showing up, being in a good head place, having fun out there, and whatever happens, happens."

On Sunday, she also competed on the uneven bars for 14.400 points, balance beam where she scored 14.566 and then soared on the floor exercise for a reward of 14.633.

That paved the way for her spectacular vault which brought the crowd and teammates Shilese Jones, Leanne Wong, Skye Blakely and Joscelyn Roberson to their feet.

Biles and her USA team will now go for team gold on Wednesday in Antwerp.

"She made it. That is all I can say, she handled her nerves, handled the pressure. It was her last event, she endured fatigue and everything," said Biles's coach Laurent Landi of the dramatic vault performance.

"So it's great. People I hope realise that once in a lifetime you are going to see a vault like that from a woman gymnast, so I think it is time to appreciate that now." (AFP)