For seven years, Kyle Chalmers was bugged by a secret, nagging doubt.
Was his Olympic gold medal in 2016 a fluke?
The thought is somewhat preposterous; unless you're Steven Bradbury, Olympic gold medals aren't won by chance.
Yet it still bothered Chalmers, who admits not fully appreciating the 100m freestyle gold he won as an 18-year-old at the 2016 Rio Olympics.
But now, after collecting the 100m freestyle world title in Japan, Chalmers knows the truth.
"I wanted to make sure ... that it wasn't a fluke," he said.
"There were times where I thought I would never get back to swimming fast.
"I wasn't overly fast for probably two years after Rio."
In between Rio and the world titles in Fukuoka, Chalmers won a swag of gold medals in his pet event.
But there were silvers at the big meets: the Tokyo Olympics of 2021, and the 2019 world championships in South Korea.
He also took silvers as part of 4x100m relay teams at the 2019 (mixed) and 2022 (men's) worlds.
And heart surgery. Shoulder surgeries. Various other injuries. Mental health battles.
Chalmers said those downers made his Thursday night triumph the ultimate upper.
"It's a moment that I have envisioned for quite some time," he said.
"I am a guy that trains to win, I don't train just to make up the numbers.
"I want to win the race every time. I am a competitive beast.
"There has been some challenging times definitely - winning (Olympic gold) at such a young age, and the expectation and pressure that comes with that.
"I'd be lying if I said I didn't have doubt in mind at times that I would be able to achieve that (world title).
"But I'm at a point now in my career where I am able to enjoy the moment, stay relaxed. I probably never felt calmer in a championship final."
Chalmers' races in Rio and Fukuoka were similar.
In both, he turned in seventh spot. In both, he unleashed a supercharged last lap - he covered his final 50 metres in Rio in 24.44 seconds; in Fukuoka it was 24.11.
His winning time in Rio was 47.58, in Fukuoka 47.15. The 0.43 seconds difference weren't by luck.
"I have had to work so much harder for that moment," Chalmers said.
"In 2016 I was an 18-year-old kid and, to be honest, I didn't really know what I achieved in that moment.
"I have had to work so hard for seven years, sacrifice so much, go through heart surgery, shoulder surgeries, some pretty bad mental health times throughout this last little period.
"So I know how much it means to me, my family, my friends. I can't wait to get home and share it with those special people.
"Next week I will go back to Port Lincoln, I will probably go back to football training on Thursday afternoon.
"Have a kick with mates and probably have a few beers afterwards to celebrate.
"And I know that is when I am really going to be able to sink in and enjoy this moment."
