Even by her own lofty standards, Saturday was a good day for Emma McKeon. The 30-year-old swimming superstar, who in Tokyo became Australia’s most decorated-ever Olympian at a single Games, added another gold medal to her haul in the women’s 4x100m freestyle relay. McKeon has now been part of that winning relay team at three consecutive Olympics.

It adds to a remarkable tally. After relay gold on Saturday, McKeon has won six gold, two silver and four bronze medals across three Games. She is now the most accomplished Olympian in Australian history – with her six golds putting her one ahead of the legendary Ian Thorpe. Add to that five world titles and 14 Commonwealth Games gold medals and McKeon must be a contender in any discussion about Australia’s greatest-ever swimmer – truly rarefied company given the nation’s illustrious history in the pool.

On Sunday, though, she will face a different challenge. After qualifying sixth fastest in the women’s 100m butterfly semi-finals on Saturday, barely an hour before she swam for gold in the relay, on day two McKeon will swim in what might be her last-ever chance for an individual Olympic medal.

Such is the depth of the Australian women’s swim program at present that, at the team’s trials in June, McKeon failed to qualify for the two individual events where she is defending Olympic champion: the 50m and 100m freestyle. The swimmer tore a muscle under her armpit late last year, which had hampered her preparations. It left just the 100m butterfly on McKeon’s program – an event in which she claimed bronze three years ago.

And so on Sunday evening local time, McKeon will swim for glory in the hope of putting an exclamation mark on a truly remarkable career. Although only 30, it seems unlikely the Wollongong local will still be swimming come Los Angeles 2028 – she has admitted she contemplated retirement after Tokyo. The two-lap butterfly could be the last time Australian fans see McKeon in solo action (although she is likely to race in medley relays later this week).

McKeon’s success for Australia is all the more remarkable because she almost quit the sport before a single Olympics. Hailing from a swimming family – her mother, father, brother and uncle all swam for Australia – McKeon was a talented junior. But at the Olympic trials ahead of London 2012, the youngster agonisingly missed out on being part of the Australian relay team by one spot.

Had McKeon been one-tenth of a second faster at trials, she would have gone to London and won gold as part of the successful relay team. She went anyway, to cheer on her brother and training partner, but spent the event contemplating her future.

“I was really upset after that, and then I actually stopped swimming not long after the trials,” she later said. “I knew I wanted to go to the Olympics, but I didn’t want to wait another four years, so I was like, ‘I’ll just stop.’”

Fortunately, for Australian swimming, McKeon did not quit. She doubled down and qualified for the following year’s world titles, in Barcelona, where she won three relay silver medals. A gold, two silvers and a bronze medal followed at the Rio Olympics, before McKeon dominated the field in Tokyo and added her name to the history books. For this quietly-spoken swimmer from coastal New South Wales, the records just kept coming.

“If I look back at that young [me], I think I was 17 when I missed London, you couldn’t have told her that I was going to go on to do this,” McKeon said on Saturday. “It’s just persisting. You have ups and you have downs. You just keep going along, keep ticking the boxes and doing everything that you can. That’s what I have done over the years.”

Speaking to journalists in the bowels of La Défense Arena, having collected her latest Olympic gold, McKeon was visibly speechless. “I can’t believe where I’m at right now,” she said.

McKeon’s final individual appearance will not be easy. The women’s 100m butterfly field is packed with talent, including American Gretchen Walsh (who set a new world record just last month and an Olympic record in the semi-finals), 2022 world champion Torri Huske (USA), 2023 world champion Zhang Yufei (China) and defending Olympic champion Maggie Mac Neil (Canada).

At last year’s world titles, McKeon finished fourth in the 100m fly. In no way is a medal on Sunday guaranteed – the Australian will have to work extremely hard to ensure a fairytale final individual outing in the Olympic pool. But given her storied career, and history of overcoming adversity, few would bet against one last dance for Emma McKeon.