Australian champion Ariarne Titmus and American rival Katie Ledecky will face off earlier than expected, with the superstars locking horns in the women’s 400m freestyle heats on Saturday evening AEST.

Titmus and Ledecky have been named in the event’s third heat, which gets underway at 7.12pm. Both are expected to comfortably qualify for the Sunday morning’s final, which starts at 4.55am. Multiple media outlets have dubbed the Titmus-Ledecky showdown as “the race of the century”.

Olympic Medallist James Magnussen said Titmus had the “weight of a nation on her shoulders”.

“The whole swim team will basically get on the back of her results and use that momentum,” Magnussen said on Fox Sports News’ Matty & the Missile in Paris.

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“Or if she was, in some unfortunate circumstance, to lose, the whole swim team starts looking at each other going: ‘Did we get out preparations wrong? Did we come over here too early? Did we peak too early? Are we doing the right type of training?’

“There’s so much pressure on Ariarne night one.”

Despite the external expectations, Magnussen predicted Titmus to thrive in the spotlight.

“I’m backing Titmus to win comfortable and actually break a world record,” he said.

“I’m going to call it now: I’m saying Titmus is our greatest swimmer of all time and after this Olympics we nationally recognise that Titumus supersedes Ian Thorpe as our greatest swimmer in history.”

Australia is also a medal chance in the 4x100m freestyle relay events — the heats get underway at 8.15pm before the men’s and women’s finals at 5.37am and 5.50am respectively.

Elsewhere, Dolphins stars Elijah Winnington and Sam Short will be vying for gold in the men’s 400m freestyle.

The mighty USA have long dominated Olympic swimming, collecting 30 medals, including 11 gold, to top the table at the pandemic-delayed Tokyo Games, ahead of Australia with nine gold and 20 in total.

However, Australia stunned the Americans by doubling their gold medal tally at last year’s world championships, setting up a blockbuster showdown over an intense nine days in La Defense Arena.

The deep-seated rivalry dates back to a war of words at the 2000 Sydney Olympics when Gary Hall Jr. claimed the Americans would “smash them like guitars” ahead of the 4x100m freestyle relay final. Australian quartet Michael Klim, Chris Fydler, Ashley Callus and Ian Thorpe celebrated their unforgettable triumph by mimicking playing guitars on the pool deck.

SWIMMING DAY 1 SCHEDULE

7pm: Women’s 100m Butterfly (Emma McKeon, Alexandria Perkins)

7.12pm: Women’s 400m Freestyle (Ariarne Titmus, Jamie Perkins)

7.30pm: Men’s 100m Breaststroke (Sam Williamson, Josh Yong)

7.45pm: Men’s 400m Freestyle (Elijah Winnington, Sam Short)

8.15pm: Women’s 4x100m Freestyle Relay (Australia)

8.26pm: Men’s 4x100m Freestyle Relay (Australia)

4:30am: Women’s 100m Butterfly semi-finals (Emma McKeon, Alexandria Perkins)

4:42am: Men’s 400m Freestyle Final (Elijah Winnington, Sam Short)

4:55am: Women’s 400m Freestyle Final (Ariarne Titmus, Jamie Perkins)

5:15am: Men’s 100m Breaststroke semi-finals (Sam Williamson, Josh Yong)

5:37am: Women’s 4x100m Freestyle Relay Final (Australia)

5:50am: Men’s 4x100m Freestyle Relay Final (Australia)