Ledecky was untouchable as she cruised to victory in 15min 23.21sec, more than a minute in front of 16-year-old runner-up Brinkleigh Hansen, who touched in 16:31.31.

Becca Mann was third in 16:35.09.

Ledecky didn’t threaten her world record of 15:20.48, set in 2018, but she used a strong late surge to improve on the second-best ever time of 15:24.51 that she had set at the Pro Swim Series in Fort Lauderdale, Florida, last April.

Since then she has gone on to win her sixth world title in the event at last year’s world championships in Singapore.

She has won both Olympic gold medals — at Tokyo in 2021 and Paris 2024 — since the 1500m free was made an Olympic event for women.

Now 28, the American who won her first Olympic gold in the 800m freestyle at the 2012 London Games is showing no signs of fading as the 2028 Los Angeles Olympics beckon.

Ledecky, the only woman to break 15:30 for the 1500m free, did so for the 10th time.

She owns the top 12 times ever and 24 of the top 25, with Italian Simon Quadrella’s runner-up finish to Ledecky in 15:31.79 at last year’s world championships now slotting in as the 13th-fastest ever.