NICK D'Arcy's long-term mentor predicts the Kawana-product is a big chance of a medal in the 200m butterfly, which gets under way in London tonight (AEST).
Brian Stehr knows D'Arcy the swimmer better than anyone, having nurtured the prodigious talent for 17 years before he relocated to Brisbane and joined Michael Bohl's St Peter's Western squad last year.
In order to win gold, D'Arcy must defeat the greatest Olympian of all time, Michael Phelps, as he chases his third consecutive gold medal in his pet event.
But Phelps showed some vulnerability in the 400m individual medley yesterday morning, when he finished fourth behind compatriot Ryan Lochte.
Also on the radar is Japanese champion and Beijing bronze medallist Takeshi Matsuda.
The competitive beast that is Nick D'Arcy has never been unleashed at an Olympics and Stehr said his former charge was more than capable of breaking the 1min 54 sec mark and earning a place on the dais in London.
"I think Nick has a very big chance of a medal in London," he said.
"We spent 17 years together, which is a very long time for a coach and a swimmer.
"And I would never under-estimate him in an event because I know he has got something special; he has got that X-factor."
The 25-year-old's 1:54.71 is the third fastest time this year behind Phelps (1:53.65) and Matsuda (1:54.01), but Stehr said D'Arcy should improve on that time based on his preparation and the added incentive of an Olympic medal.
"I think he is going to have to go a second or a second-and-a-half faster if he is to have a chance over there," Stehr said.
"And I think he has absolutely got a 1:53 in him and he could go faster.
"Nick doesn't need anybody else in the pool to motivate him. He knows what is expected and Bohly told me he is one of the hardest workers he has ever seen."
Bohl has previously played down talk of a showdown with Phelps, citing it as meaningless unless both swimmers were in the final and even then the big American would be tough to de-throne.
He said D'Arcy's focus was instead on the heat swim and producing a personal best, which would hopefully earn him a medal.
"It might sound like a cliche, but Nick really just has to take it swim by swim. He can't go over there thinking about finals or swimming against Michael Phelps because there are 90 swimmers in the heats, which he has to get through first," he said.
"Then it becomes 16 in the semi-finals and he has to get through that, then he can worry about the eight guys in the final."
D'Arcy will compete in heat five alongside Phelps from 7.21pm with the semis to be contested at 5.32am tomorrow. The final is at 3.49am on Wednesday.