Ariarne Titmus sets up rivalry for the ages with win over Katie Ledecky

Aussie teen Ariarne Titmus pulled off one of the all time upsets when she beat Katie Ledecky at the world titles — but the win may have come at a big cost.

GWANGJU, SOUTH KOREA — JULY 21: Ariarne Titmus of Australia reacts in the Women's 400m Freestyle Final on day one of the Gwangju 2019 FINA World Championships at Nambu International Aquatics Centre on July 21, 2019 in Gwangju, South Korea. (Photo by Clive Rose/Getty Images)

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Australia’s newly crowned world champion Ariarne Titmus knows that by beating Katie Ledecky she may have just poked the bear.

But the Tasmanian teenager also has a subtle message for her great American rival, her best is yet to come …

Despite pulling off one of the greatest upsets in swimming history by mowing down the previously unbeaten Ledecky to win the 400m freestyle gold at the world titles in South Korea on Sunday night in a career-best time, Titmus declared she’s not the finished product yet.

Ariarne Titmus reacts after pulling off one of the greatest upsets in swimming history. Picture: Clive Rose/Getty Images

“I was pretty happy with the swim, but I can still see room for improvement,“ Titmus said.

Her coach Dean Boxall agreed:

“I think she could have executed it a little bit better. It was a good swim, of course. That’s racing. But it could have been better,” he said.

“I thought Arnie missed the beat on a few things but just that fight in her came through, especially since I thought that she nearly missed an opportunity there.”

It’s that endless search for perfection for Australian swimming’s most determined duo that has enabled the Terminator to do what no-one else thought was possible, and the way she did it was almost beyond belief.

WOW!!! Ariarne Titmus WORLD CHAMPION!!! #worldchamps @DolphinsAUS What a swim!!!

— Giaan Rooney (@GiaanRooney) July 21, 2019

Katie Ledecky gets run down by 18-year-old Australian Ariarne Titmus in the last 50 meters, loses a major international 400m freestyle for the first time. pic.twitter.com/Vh3vMeZbTC

— Nick Zaccardi (@nzaccardi) July 21, 2019

After trailing for the first 200m, Ledecky made her move, opening up a body length’s lead when the pair turned for home and it looked all over.

But when Titmus started to claw back, the American had nothing left and was powerless to stop the 18-year-old steaming past her.

“I just got to the last turn and felt like I just tightened up,” said Ledecky.

“My legs were just dead. Obviously, Ariarne took advantage of that. This stings a little, unfamiliar and different.”

Although she was more gracious at the medal presentation, Ledecky did not initially take her defeat well. When a beaming Titmus turned around to face her after getting her hands on the wall first, the American turned her back on the Australian and spoke instead to one of her American teammates.

Katie Ledecky turns her back on Ariarne Titmus after the women's 400m freestyle final. Picture: Ed Jones/AFP

Her message to Titmus was clear as well. She’ll see her in Tokyo next year for the Olympics.

“Ledecky, she looks pissed off, angry,” Boxall said.

“She’s going to come back. She’ll be like a caged tiger coming out.

“Is it great for Arnie to win? Yeah, sure. But what does it do for Ledecky? Ledecky is still the Olympic champion, she’s the world record holder. Arnie is still the underdog.

“She knows she didn’t swim that race well and she knows that Katie had a misfire and that she still has two seconds on her. Something broke in Katie.”

Titmus also expects Ledecky to come back with a vengeance.

“Katie is a true champion, to do something like this, I suppose every girl who does middle distance freestyle dreams of doing,” Titmus said.

“I am excited that I could do that, but next year is the Olympics and I am sure she will be back next year in her best form and I am excited for the chance to race her again.”