• Brilliant US gymnast claims third gold of possible five at Rio 2016 • Hong fell after attempting almost mythical triple twisting Yurchenko

Simone Biles is only 19 years old and stands just 4ft 8in and yet she looms as a giant over the other gymnasts at Rio 2016. Already being called the greatest gymnast of all time, she won her third gold here on Sunday simply by sitting in a green folding chair at the Olympic Arena.

Biles’ mere presence is forcing her opponents to try risky and dangerous things in the hope of somehow defeating her. Instead they fail and wind up handing her more golds. She barely has to try. On Sunday, in the first of her individual competitions – the vault – she crawled inside the head of North Korea’s Hong Un-jong who is her biggest rival on the apparatus.

Hong is one of the most feared gymnasts on the vault. Reportedly, video exists of her once completing a triple-twisting yurchenko, which is so challenging and dangerous few have dared to try it.

Biles herself cannot do a triple-twisting yurchenko, calling it “crazy” and settling for a double twist. But given Biles’ supreme dominance here as she goes for a record fifth gold medal Hong had no choice. If she was going to beat Biles she was going to have to do the triple-twisting yurchenko. As fate would have it, Hong was the first competitor. Her first attempt, without the triple-twisting yurchenko, got her a 15.400. An excellent score, but not good enough to beat whatever Biles would put up. This meant she had no choice to but to try the “crazy” version.

It did not work. Hong completed the spins twisting down like a diving torpedo but when she hit the mat, she fell, landing on her back. She slowly picked herself up and stumbled to the chair area where she sat sullenly on the floor, picking tape off her legs. When her score, 14.900, flashed on the scoreboard she dropped her head. The vault competition was essentially over.

This left the rest of the competitors to run through their routines in a hopeless pursuit of Biles’ brilliance. Once they were finished, Biles – scheduled to go last – walked up and nailed her first vault with a 15.900.

She ignored the roar of the crowd still dazzled by her first vault, saying she needed to concentrate on her second, which required a move she is still trying to nail down.

“All the girls on the floor here are perfectionists,” Biles’ coach, Aimee Boorman, said.

On her next attempt, Biles scored a 16.033. She smiled, clapped and then walked away. Winning a gold never seemed so easy. She stood in the bench area with the other gymnasts, with no drama in the moment. Whatever figure flashed on the screen was going to be a gold medal number. She barely registered excitement at the 15.966 that appeared. “I was happy, but I kind of knew before the score came up that I had won,” she said.

Later she stood in a hallway below the Rio Olympic Arena stands and gazed admiringly at the gold medal that dangled around her neck. It was much heavier than she expected and maybe even more fragile.

A few days ago she and team-mate Aly Raisman posed for a television interview with their multiple medals around their necks. They noticed that when the medals knocked together the paint on both started to scratch. “So we aren’t going to do that any more,” she said.

In many ways, the vault represented Biles’ biggest impediment on her way to five gold medals. It is one of her best events but it is also the one that requires the fewest manoeuvres which means a specialist like Hong could defeat her.

But once Hong tumbled to the floor on her second attempt there was no fear that Biles would lose the gold.

Russia’s Maria Paseka finished second with a score of 15.253 and Sweden’s Giulia Steingruber took the bronze with 15.216. Hong finished sixth.

Next for Biles in her pursuit of Olympic Games gold perfection is the balance beam, which will be held on Wednesday, and the floor exercise.

Then will come an explosion of attention back in the United States where Biles will no doubt be a bigger star than before she left for Rio. The thought of what lies ahead seemed to amuse Boorman, who laughed when the subject came up.

“I don’t think she understands the explosion,” Boorman said. “They are all in their little Olympic bubble.”

Soon that bubble will pop. At some point, Biles is going to realise just how big she has become. She has had a remarkable ability to make her competitors shrivel in fear. Even when all she does is sit on a chair.