These were supposed to be familiarisation Games for Stubblety-Cook, warm-up Olympics getting him ready for the real thing in Paris in 2024. That was the way he was thinking. Certainly, his mother Julie was deliberately keeping her expectations low even though her son came into this event with a fourth placing at the world championships and the second-fastest time on the planet this year.

But so steadily – and surprisingly stealthily – he progressed through the heats and semis here that no-one really gave him a chance of winning, even when he qualified fastest for the final. And that was exactly how it played out in the gold medal-decider, with the Netherlands' Arno Kamminga leading the field out in 1:00.09, more than two seconds under the World Record pace.

The 22-year-old Australian was back in fourth place, one of seven swimmers going faster than Russian Anton Chupkov’s World Record pace. Those who had paid close attention, however, might have sensed what was about to happen. Stubblety-Cook comes home like a train without a station. Indeed, he made up an astonishing two seconds on Kamminga in the final lap alone as he swept past his rivals to claim the gold medal in a new Olympic Record time of 2:06.38.

Kamminga held on for the silver in 2:07.01, with Matti Mattsson winning only the fifth swimming medal for Finland with his 2:07.13 clocking.

“You only can be an underdog once and I had that luxury here today,” Stubblety-Cook said after the event. “I was just happy to be here and even more happy with the result.”

He knows the way he swims the race causes all his supporters’ stress. In fact, it causes him some stress as well but that is the way nature has equipped him and so he does his best.

“I knew there would be a few people who were going for it early. That’s the way it was five years ago in Rio and I knew that someone would be up there. I’m just glad I was able to execute my race plan and do what I do.”

Clearly, he knows his short-term swimming history but also his long. When a journalist stumbled over who had been the last Australian to win this title, he was able to help them out.

“At the last Tokyo Olympics (1964, when Ian O’Brien won Australia’s second gold in this event, following on from John Davies in 1952). “It’s an honour,” he said, savouring the fact that he had just broken a 57-year drought for Australia.

Chalmers equals his best for thrilling silver

Having produced one male Olympic swimming champion at these Games, Australia almost produced two within the space of an hour. Agonisingly, however, defending champion Kyle Chalmers (48.08sec) was out-touched at the finish of the 100m freestyle final by his arch-rival and close friend, American Caeleb Dressel (47.02sec).

It looked for all the world that Chalmers would become the seventh Australian to defend his Olympic title – and the first male to do so in the blue riband event – as he turned third at halfway. But, alas, it was not to be. He was forced to glide ever so slightly at the finish, his characteristic charge leaving him just short of the wall, whereas Dressel finished on a full stroke. That was all it took to account for the .06sec separating them.

Chalmers watched some recent history of his own making in the lead-up to his final, replaying a video of his family’s reaction to his gold medal swim in Rio. To see his grandfather so happy for him.

They would have been proud of him again today, as he wrapped Dressel in a bear hug as soon as the two swimmers had emerged from the pool.

“That makes it even between us,” he said. “Maybe a Round 3 decider in Paris in 2024.”

Still, going so close to defending the title was starting to sink in.

“To have done my equal best time in an Olympic final, half a second faster than I went in Rio, knowing there was not a single thing I could have done differently, that’s pretty satisfying. But it is a little bitter-sweet. To get silver is special but to be so close, it does hurt a little bit.”

Name another Olympian who has had heart surgery three times between winning gold and silver at the Games. And frankly, that wasn’t the worst of it. Chalmers was forced to have shoulder surgery just seven months ago and that normally is curtains for a sprinter. Since then, he has had 12 cortisone injections to allow him to operate. Yet still he presented in Tokyo with no excuses.

He downplayed suggestions that the fact that he only breathes to his right meant that he had no idea how Dressel or bronze medallist Kliment Kolesnikov of Russia (47.44sec) were travelling. In fact, it had no impact.

“I swim with my eyes closed,” he explained.

Relay girls break own World Record for 4x200m bronze

There was another agonisingly close finish for the Dolphins when Australia broke its own World Record in the 4x200m freestyle but still were relegated to the bronze as China stunned everyone by taking 0.17sec off the mark Australia had set at the 2019 World Championships. Not even the GOAT, American Katie Ledecky could pull the Chinese back, though she gave it her best shot, finishing just 0.4sec behind.

Australia had entered a completely changed quartet for the final, which caused some comment, although the team for the final went 3.32sec faster than the side used in the preliminaries. Australia front-end loaded its team, sending in dual Olympic champion Arnie Titmus and Emma McKeon for the first two legs but the Chinese swimmers weren’t to be denied, leading at both changeovers. Thereafter it was looking problematic for the Australians, especially with Ledecky still to come for the Americans, but Madi Wilson and Leah Neale swam great legs to keep Australia in the mix in what was an incredible race.

“It was pretty crazy,” said Neale, who had just had her first and last swim of the Tokyo Olympics.

Titmus was hard on herself. “I would have liked to have done a bit more for the team. I feel like I should have been better,” she said. “It’s been a big couple of days, so I’m happy with a podium.”

It was left to the veteran of the team, 27-year-old McKeon to put the whole performance in perspective. “We were under our own World Record time, and we all gave 100 per cent, so you can’t ask for more than that. To get on the Olympic podium is very special.”

McKeon and Campbell cruise into 100m freestyle final

The men’s 100m freestyle final could hardly have been more memorable but the women’s 100m freestyle final is shaping up as one for the ages. McKeon clearly is the one with the speed at this meet and while she was fractionally slower than her 52.13sec Olympic Record from the heats, she still was fastest into the final in 52.32sec.

Worryingly, the young woman who gave Titmus such a fright in the 200m final, Hong Kong’s Siobhan Haughey looks to have unfinished business at these Olympics and was second-fastest in 52.40sec, just ahead of Australia’s other champion, 29-year-old Cate Campbell (52.71sec).

She is keeping it simpler at these Olympics, not stoking the pressure on herself as she did in Rio five years ago.

“I’m taking a step back and really soaking up every moment,” she said. “It really is a privilege to be here and sometimes you can forget that.”

McLoughlin and Throssell fight bravely in finals

Jack McLoughlin, the silver medallist here in the 400m freestyle, was never quite on the pace in the inaugural Olympic 800m freestyle, finishing a couple of seconds outside his best as he clocked a neat 7min45sec for fifth.

Robert Fisk of the United States came from the clouds to claim the gold in 7.41.87, ahead of the man who had attempted to lead for the entire race, Italy’s 1500m champion Gregorio Paltrunieri (7/42.11).

Brianna Throssell just made it through to the final of the 200m butterfly in eighth place, but sadly Mitch Larkin (200m individual medley), Tristan Hollard (200m backstroke) and Jenna Strauch (200m breaststroke) all were eliminated at the semi-final stage. 

Wayne Smith

Zac times swim to perfection as Dolphins win another set of medals