Australian Olympic debutant Brendon Smith has pulled off a stunning personal best time in the 400M individual medley to qualify fastest for the final.
Smith's rapid swim in the final heat of the event not only saw him enter the final as favourite, it also resulted in the previous gold medal frontrunner, Japan's Seto Daiya.
Daiya had streaked ahead of the pack over the early legs, and was almost two body-lengths ahead of the field heading into the freestyle leg.
It was there however, that Smith discovered a further turn of pace to reel in the home hero.
Smith earned his place on the Australian team by setting a new Australian record at the Olympic Trials in Adelaide earlier in the year.
Swimming legend Ian Thorpe, on commentary for Channel 7, described the heat result as a 'massive boilover'.
The 21-year-old, who hails from Melbourne, qualified fastest in a time of 4:09.27.
Smith will have his chance for gold when the final is held on Sunday.
Fellow Australian Se-Bom Lee was eliminated from the final in an earlier heat.
Aussie swimming coaches backing 'IQ' of brightest stars
Australian swimming's head coach calls it "competitive IQ".
And Rohan Taylor says it now decides Australia's swimming fate at the Tokyo Olympics.
"On paper, it looks like we are (looking good)," Taylor said ahead of Saturday's first session at the pool.
"But you know when you come to this competition, it's about who has the competitive IQ to perform under pressure.
"The American system breeds competitive athletes, their whole college system, the best competitive people come out of the top.
"But we believe this year we have some really strong competitive, strong mentally competitive athletes."
Of the 14 individual Olympic swimming races, an Australian ranks top in seven and an American top in five.
And Australia boast exceptional strength in relays, led by a women's 4x100m freestyle team seeking to win gold for a third Olympics in a row.
But Swimmming Australia head coach Taylor dodges any medal predictions.
The nation's best Olympics at the pool is eight golds at Melbourne's 1956 Games.
For all Australia's strengths, Taylor is wary of the US, as is customary, flexing its muscles at an Olympics.
"The Americans have proven historically at the Olympics that they perform," Taylor said.
"So for us, you know they're the standard that were striving for. And they rightly so have deserved that."
Watch 'Mind Games', the new series from Yahoo Sport Australia exploring the often brutal mental toil elite athletes go through in pursuit of greatness:
Click here to sign up to our newsletter for all the latest and breaking stories from Australia and around the world.