GLASGOW (Reuters) - At just 4 feet 9, Simone Biles' petite frame barely reached the ears of Olympic champion Gabby Douglas, when the American team were introduced to the crowd at the gymnastics world championships in Glasgow on Tuesday.
Yet it is thanks her lack of height that the pint-sized dynamo is head and shoulders above her rivals and is already being feted as the greatest gymnast to have graced the sport -- even though she has yet to make her Olympic debut.
Under the careful guidance of her lifelong coach, Aimee Boorman, Biles has become such a force in the sport that her rivals now think she is "wired like a robot".
And the fact that she has barely grown since becoming a senior has enabled the 18-year-old to sustain an unprecedented level of performance.
"She stood out from the beginning. She’s been special from the beginning. When she was younger and competing at the lower levels, she had that star quality," Boorman told Reuters in an interview.
"She has this ray of light that shoots out of her when she competes. Even when she was eight years old, she could draw in the crowds."
In just three years as a senior, Biles has collected a stack of medals -- including seven golds at the worlds -- and now stands on the verge of becoming the first woman to win three successive all-around titles at the world championships.
While Biles did not want to think too far ahead about the possibility of creating history at the Hydro Arena on Thursday, preferring to "blank it all out", Boorman said: "It’s really cool (that she could achieve that).
"She feels a lot more pressure because everybody is saying no one has ever been three-times world champion, and that sticks in her head."
That pressure did not seem to be evident on Tuesday when Biles' performance dazzled as brightly as her sparkling red leotard as the U.S. swept to a third successive team gold.
She earned 15.966 for her soaring and gravity-defying Amanar vault, 15.200 on the balance beam -- a routine that included her spinning around 900 degrees on her right toes without a wobble in sight -- and 15.733 on the floor.
Her displays have left many of the sport's greats gushing, with 1984 Olympic champion Mary Lou Retton declaring: "She's the most talented gymnast I’ve ever seen in my life. I think she’s unbeatable."
That is certainly true when it comes to all-around competitions. Over the past two years, Biles has enjoyed a 100 percent record in the event that tests skills across four apparatus.
But having become a senior at the start of an Olympic cycle, Boorman knew if Biles wanted to have a shot at glory at the Rio Games, she would have to sustain her levels of excellence for four full years -- a stretch that is beyond most elite gymnasts.
"One of things we faced with her becoming a senior just after the 2012 Olympics was that nobody has ever sustained (being on top) that long. You can’t come out on top in your first year and expect to stay on top," explained the 42-year-old Boorman.
"So it’s been a balancing act of keeping her healthy and making sure she has fun.
"Overall I think she’ll be able to hold up as she doesn’t need to add any difficulty to her routines, she just has to maintain what she’s got.
"This (Olympic cycle) has been the perfect timing for her as she’s petite and hasn’t grown a lot since she became a senior."
As Biles and Boorman head into the most important phase of their 12-year partnership, the coach who considers herself "as the cool aunt rather than a surrogate mother" knows the most important thing she can do for her star pupil is to keep things real. So does that mean they argue?
"Always. We’re with each other close to 40 hours in the week so there’s obviously going to be conflict," the mother of three boys said.
"But we’re really good at turning the page. She knows that no matter what happens the day before, the next day she comes into the gym I don’t hold a grudge or any animosity.
"I know people think she’s an alien but she is actually human. She has bad days too.
"So when Simone fell at the U.S. Championships, it was like ‘Oops. Oh my goodness. What happened? Simone fell. Is her wiring not correct? Somebody check her wiring because that robot who always hits (her routines) just fell'.
"No, she’s not a robot - she’s a human."
Reporting by Pritha Sarkar, editing by Neville Dalton