KANSAS CITY, Mo. — The competition isn’t the judges, the rest of the field or even the sport she’s dominated for the better part of a decade. Simone Biles conquered all of them long ago.

What drives Biles is the voice in her head, the one that tells the best gymnast in the world that perfection is the only standard, even while attempting skills that no other woman can match.

That’s why her anger was so palpable during the opening night of the U.S. women’s gymnastics championships Friday. She shorted her triple-twisting double-flip in her floor routine, a mistake that put the Olympic champion on the verge of tears. Her uneven bars were messy and her vault was dangerously close to disaster.

That her all-around total of 58.650 led Sunisa Lee by 1.750 — putting a sixth national title easily within reach heading into today’s finals — was immaterial.

“I still get really frustrated because I know how good I am and how well I can do,” she said. “So I just want to do the best routine for the audience and for myself out here.”

For Biles, that means packing her sets with an unparalleled level of difficulty, a choice she makes not because of ego but out of respect for her immense talent.

She didn’t have to add the triple-double to the end of her first tumbling pass. She just wanted to see if she could do it. She didn’t have to throw in a double-twisting double-flip dismount on the beam. But after toying with it in practice for the last five years just for kicks, she figured it was time to see if she could do it when it mattered.

The results Friday were mixed. She was a little too excited during her floor routine and the inability to control her adrenaline cost her. She shorted the landing, lunged forward and briefly placed both hands on the ground to steady herself.

“I’ve never fallen on one or anything,” Biles said. “Just to make a mistake like that, it kind of irritated me.”

And it didn’t go away. She practically rolled her eyes after both of her vaults. Her uneven bars — an event she says she’s been fighting with for a while now — lacked their usual crispness.

A smile of relief finally emerged after she drilled her double-twisting double-flip dismount on the beam. Such is the world Biles has created for herself that on a night when she finished with the top score in three events (vault, floor, beam) and tied for fourth on the other (bars), she seemed more annoyed than elated.

That’s not necessarily a bad thing.

“I’m actually happy she’s so upset because it means she cares so much and we can work with it,” coach Laurent Landi said. “If she would not care, it would be hard to go back in the gym and practice it.”

The Americans are in the process of trying to figure out who will join Biles on the 2019 world championship team. The field looks muddled with the selection camp a month away.

Lee, at 16 one of the youngest competitors in the 17-woman field, put up the top bars score (14.750) and was third in two other events. Jade Carey, who is eyeing an automatic spot on the 2020 U.S. Olympic team as a vault specialist while also hoping to prove she is among the best all-around Americans, put together four solid routines and was third at 56.100.

Riley McCusker was fourth despite a fall on uneven bars to end the night. Leanne Wong and Trinity Thomas were tied for fifth. Jordan Chiles, a teammate of Biles at World Champions Centre in Houston, was seventh.

Morgan Hurd, the 2017 world champion, appeared to be on her way to bouncing back from an uneven performance in the Pan American Games last week until her floor routine, when she bailed out of her second tumbling pass to fall from second to eighth overall.

“I think it was just a fluke and I’ll deliver better on Sunday,” said Hurd, who stressed she doesn’t believe she’s tired even while competing in her third major competition in a month.

Biles might opt for an easier beam dismount today. Otherwise, everything stays the same. That means taking another shot at the triple-double, another chance to join the two men who pulled it off in competition. Playing it safe simply isn’t her style.

That’s why she doesn’t take solace in simply coming close. It’s why she lets herself get upset when most other athletes would give themselves a pass for trying something so daunting.

“If she thought otherwise, she wouldn’t be No. 1 in the world,” Landi said. “If you think this way, you’re already losing.”

Something Biles hasn’t done for six years and counting.