"I'm confident with the work I've put in since the last Commonwealth Games," he told the Herald. "I'm five seconds faster than I was going into the last Games, so I think that's exciting.
"I do feel like I belong here, among the best athletes in the world. I'm pretty confident and as an athlete if you want to perform well you have to have confidence.
"That's where I think it starts, so I'm happy I have the confidence that I can perform well on the world stage."
That self-belief was certainly clear in Tokyo, where Clareburt qualified for the 400 IM final with the second-fastest time. If he had repeated that swim the next day, it would have been good enough for the silver medal, but Clareburt was unable to follow his race plan.
Watching from the stands as his star pupil failed to find his typical acceleration in the latter stages, coach Gary Hollywood knew something was wrong.
"I could see when he came out for the final, he was dishevelled," Hollywood said. "He was where he needed to be, in the silver-medal position with 25 metres to go, but he couldn't go to that next gear.
"He didn't slow down - he swam the same split on the last 50 as the first 50, but our race is to swim faster in that last 50, and he just didn't have the energy to do it."
Unbeknownst to his coach, sleeping soundly in the adjacent room, Clareburt found himself wide awake for much of the night. That misfortune was particularly galling given what Hollywood had been told by someone who knew exactly what it took to become an Olympic champion.
"I was gutted," Hollywood said. "Ryan Lochte's coach, Gregg Troy, who's working with us 'til Paris, said, 'The guy can win a gold medal'. And I said, 'I know he can'."
While Lochte won six during a glittering career, Clareburt knows New Zealand would be more than happy with one.
Time is on the 23-year-old's side, and before he heads to Paris to break this country's Olympic medal drought in the pool, the next week will likely confirm his capability of doing just that.
Clareburt finished fourth in the 400 IM at last month's world championships in Hungary, despite having his preparations disrupted by Covid, and recorded the fastest time of a Commonwealth swimmer.
After a training camp in Mallorca that he described as "one of the best months of my life", Clareburt is ready to reward a public that was captivated by his Olympic efforts - and ready to put in a performance that will leave him sleeping soundly in satisfaction.
"It's pretty cool to know that people are following along on your journey and want to see you do well," he said. "The 400 medley has moved forward a lot so it's probably going to be a lot faster and a medal will be harder this year. But that's another challenge and it makes it more exciting."