Despite coming less than a tenth of a second off breaking her own world record at the Australian Swimming Trials earlier this year, Kaylee McKeown was frustrated.
She was disappointed with the way she executed a swim in which her coach, Michael Bohl, said was slightly rushed through the first 50 metres.
It shows the standards that McKeown — a four-time Olympic medallist, defending champion in the 100m and 200m backstroke — holds herself to.
She is also a three-time world champion at every backstroke distance available to her.
ABC Sport is live blogging every day of the Paris Olympics
So that's why, when she saw that she had swum 57.41, just 0.08 seconds outside her world record, she didn't like what she saw — not that she said that.
"I'm just happy to still be sitting around that time," McKeown said at the time.
"There's not many people in the world who are doing that at the moment."
Not many it's true, but there is one.
McKeown, who has admitted to feeling anxious ahead of this Olympics and other major meets, and has even banned herself from social media at these Games, professed to being "nervous" about what that one person could do in their trial.
It turned out, with good reason.
American Regan Smith, whose record McKeown beat at Australia's 2021 Olympic trials, not only broke McKeown's world record by 0.20 seconds at the US Trials in Indianapolis, but broke free of the mental restraints she said were holding her back up til then.
Smith, who broke the world record in 2019, admitted she never felt she would get back to the level that saw her hold the title of the world's leading backstroke swimmer until she changed her outlook.
"I just didn't have it up here," she said in the trials, pointing to her head after that blistering swim.
"Now, tonight, I'm in a much different place in my life [than 2021].
"The pressure is different. The expectations are different."
The expectations among a Paris crowd that has regularly featured a huge number of flag-waving American supporters is that she betters the bronze medal she won, behind McKeown, in Tokyo.
That mental focus is so key at these Games, where the margins are so fine and the stakes so high.
Neither woman spoke to the media after their semifinal swims. They are both too laser focused on what is needed to be done.
Given how strong both these women are, this race is arguably the key individual battle in the traditional Australia vs America pool war.
But, Michael Bohl thinks that the battle will be won in the head just as much as in the pool.
"We always talk about the Olympics being that unpredictable environment," he said in Brisbane.
"There's so much going on, it's chaotic.
"It's not the physical challenge. It's more the mental challenge of being in that environment where everyone knows it's once every four years."
Except, of course, that this is just the first battle between these two at this Games.
Both women are capable of winning multiple medals at these Games as multi-talented and multi-faceted stars at the peak of their powers.
McKeown will compete in the 200m back and the 200m IM, Smith the 200m back and 200m fly.
"I'm excited for the battle that we will have in Paris," McKeown said in Brisbane.
It was a battle joined on Monday night after just 0.02 seconds split them from the morning's heats.
McKeown was drawn in the second semifinal at Paris La Défense Arena alongside American Katharine Berkoff, who became just the fifth woman in history to record a time under 58 seconds at the US Trials, and fellow Australian Iona Anderson.
Smith was drawn in the first semi, alongside Olympic silver medallist from Tokyo, Kylie Masse.
With such talent to come, that first semifinal had to be quick, and it was, Smith leading home Masse with a time of 57.97, the Canadian swimming 58.82 ahead of her compatriot Ingrid Wilm (59.10) in third.
McKeown knew what she needed to do.
She went through the first 50 slightly slower than Smith and, after a tremendous battle down the final 50 with Berkoff, touched in 57.99.
Job done, the first skirmish met between two combatants that will leave nothing out there in front of 15,000 supporters on Tuesday night.
McKeown will not be alone in the final, with 18-year-old West Australian Anderson doing brilliantly to also make the final as the fourth-fastest qualifier in a time of 58.63, just fractions outside her personal best.
It sets up what will be a thrilling final in which all the qualifiers were split by just 1.53 seconds.
Given there will be two French women in the final as well, Beryl Gastaldello and Emma Terebo, the atmosphere promises to be as electric as any, with star turn Léon Marchand and the carnival of joy that encircles his every move at these Games set to also race.
But while their focus is on Léon, they would do well to check out the 100m backstroke, which could be among the tightest races of the week.
- The Women's 100m Backstroke Final is scheduled to start at 4:56AM AEST on Wednesday July 31. ABC Sport is live blogging every day of the Paris Olympics.