Simone Biles heads into the Olympics bidding to crown the greatest gymnastics career in history with only herself to beat.
The 24-year-old American superstar has not lost an all-around competition since 2013, an eight-year era of domination that has encompassed 19 world championship gold and four Olympic golds.
In Tokyo, Biles is poised to become the first woman in more than half a century to retain the all-around title, and could well end up equalling Soviet gymnast Larisa Latynina's record of nine Olympic gold medals.
To do that, Biles will need to win four individual events -- all-around, floor, vault and beam -- while leading the United States to victory in the team competition. Few are betting against her.
In fact, Biles has been in a league of her own for so long, she has recently taken to wearing a leotard decorated with silver rhinestones in the shape of a goat's head -- a reference to her being regarded by many as the "G.O.A.T" -- greatest of all-time.
In other sports, that sort of confidence might risk being perceived as arrogance. Where Biles is concerned, it is more a matter of fact. Biles herself says the "G.O.A.T" design was meant to inspire others.
"I just hope that kids growing up watching this don't or aren't ashamed of being good at whatever they do," she said in a recent interview.
"I want kids to learn that, yes, it's okay to acknowledge that you're good or even great at something."
This year, Biles has underscored her greatness by becoming the first woman ever to pull off a Yurchenko double pike -- a complex, gravity-defying vault that no other woman has attempted in competition.
- Risk without reward? -
Whether Biles -- who already has four signature moves named after her -- will attempt the move in Tokyo remains to be seen.
The International Gymnastics Federation refuses to acknowledge the added difficulty of the move by giving it a start value that is broadly in line with less difficult vaults, meaning that as far Biles is concerned, there is additional risk without reward. A similar criticism has been levelled at the scoring for Biles' signature double-twisting, double-back beam dismount.
Biles believes the scoring of the two moves is being kept artificially low in order to prevent her from running away with the competition.
"They're both too low and they even know it," she told the New York Times earlier this year. "They don't want the field to be too far apart. And that's just something that's on them. That's not on me."
The mere fact that Biles is returning to defend her title is unusual.
At 24, she would be the oldest winner of the Olympic all-around crown since Vera Caslavska won the second of her two gold medals in 1968 at the age of 26 years and 171 days. Every winner of the title since 1976 has been a teenager.
Biles admits that last year's pandemic-induced postponement of the Olympics -- and the thought of having to subject her body to another year of punishing workouts to maintain fitness -- prompted thoughts of retirement.
"I wanted to give up," Biles said earlier this year. "Once it was postponed it was, like, I've gone too far to give up now."
Biles says she has also grown in confidence in recent years, often leading criticism of USA Gymnastics (USAG) and the United States Olympic and Paralympic Committee over their handling of the Larry Nassar sexual abuse scandal.
- Olympic swansong? -
In 2018, Biles revealed she was among the hundreds of gymnasts who was sexually abused by Nassar, the former Olympic team doctor who is now serving a life prison sentence for his crimes. Biles has since led calls for USAG and the USOPC to hold a wide-ranging investigation into the scandal.
When USAG tweeted a birthday message to Biles last year, she responded bluntly: "How about you amaze and do the right thing -- have an independent investigation."
Biles says that her position of prominence helps maintain pressure on USAG and the USOPC. "I'm still here, so it's not going to disappear," she told Glamour magazine recently. "We have power behind it."
For how much longer Biles remains on the Olympic stage is uncertain however. Though she had previously sworn to retire after Tokyo, she has since left the door open to competing in Paris in 2024 as a specialist following discussions with her French coaches Laurent and Cecile Landi.
Biles, who took 18 months off after the 2016 Olympics, is planning a 36-stop tour of the United States after Tokyo.
"My main focus is Tokyo," she told reporters in April. "After that I have a tour, and then we'll have to see."