The Australian may not have won the most medals in the pool, but it was the significance of her 200m and 400m freestyle victories that made her performance so impressive.
It is a different kind of achievement to that of Caeleb Dressel, who has been an all-conquering champion since 2017 and was the odds-on favourite to win the three individual titles he did in Japan.
There was less certainty around Titmus’ events, given that the 20-year-old was on her Olympic debut and hadn't experienced quite the same level of World championship domination. There was also the small fact that she was going up against the reigning Olympic champion and arguably the greatest female swimmer of all time in all three of her events.
Ariarne Titmus: silencing the doubters
Ever since Titmus beat Katie Ledecky in the 400m freestyle final of the 2019 World Championships, an intense media spotlight has been thrust upon her.
The swimming world wondered if she could repeat that feat, given that Ledecky was suffering from illness at the time and would be extra motivated to avenge that defeat.
The coronavirus-enforced delay to the Olympics only served to amplify the narrative surrounding their re-match, which quickly became one of the most hyped-up rivalries across any sport in the run-up to the Games.
The race itself didn’t disappoint.
Ledecky took the early lead, but Titmus showed the calmness and maturity of a seasoned veteran to sit on the champion’s shoulder, waiting to pounce. The moment came after the third and final turn going into the last 50m, when the Australian glided past and kept a stroke ahead until the wall to claim the gold medal.
Showing predatorial instincts on the final straight to hand Ledecky her first Olympic loss in an individual event, Titmus’ nickname ‘The Terminator’ had never been more apt.
The Aussie looked happy but exhausted in the water, surely feeling a mixture of joy and relief that she had delivered.
"It’s one thing to be swimming fast in the lead-up but it’s tough to be able to do it when it matters." - Ariarne Titmus to NovaFM.
There was nothing but mutual respect between the pair afterwards.
“I just thanked her,” Titmus said of Ledecky. “I wouldn’t be here without her. She’s set this standard for middle-distance freestyle.
"If I didn’t have someone like her to chase I definitely wouldn’t be swimming the way I am.”
Thankfully Titmus’ coach Dean Boxall was on hand to celebrate for both of the Australians, with his wildly enthusiastic cheering and air-punching ensured that he was turned into an internet meme.
Entering the Australian record books
Titmus couldn’t afford to be too animated, however. Champion that she is, her focus had already shifted to her next duel in the pool with Ledecky two days later: the 200m free.
The stacked field for this event ironically meant for a less intense run-up for Titmus and Ledecky. With the likes of Olympic gold medallists Federica Pellegrini and Penny Oleksiak also lining-up in the final, the focus was more spread out.
But Titmus stepped up to the plate once again, producing a typically scintillating final length to catch Ledecky - who finished fifth - before soaring ahead of the rest of the field to win her second gold medal.
In doing so, Titmus joined legendary swimmers Shane Gould and Ian Thorpe as the only Australians to win the 200 and 400-metre double at an Olympic Games.
“She is going to have to grow into being Australia’s new sporting heroine,” Gould, who went to the same high school at Titmus told SMH. “She’s a good learner and has good people around her.”
An exciting clash to come at Paris 2024
The 800m proved a step too far for Titmus, who had to settle for second place behind Ledecky in what is the American’s favoured event.
But a silver medal and a new national record ensured that Titmus left the pool happy.
"I think my stroke is more suited to the shorter events," she said, "but I'm still going to continue with the 800m.
"I'm a silver medallist (in the 800m freestyle) at the Olympics, so I'd be stupid not to continue training for the race."
Their rematch at the Paris 2024 Olympics, in just three years' time, has the potential to be another classic.
Writing her own story at Tokyo 2020
Despite being just 20-years-old, the road to Tokyo was a long one for Titmus.
Her family relocated from Tasmania to Queensland in 2015 when she was 14, in search of the best coaching and competition to nurture her talent.
She reflected upon this after winning her second Olympic gold medal, saying: "I'm just from a small town in Tassie, and this goes to show that if you believe you can do something you can 100 per cent do it."
Since 2019, she has been defined by one amazing victory over Ledecky.
Now, she has written her own glorious Tokyo 2020 story.