Ledecky, 28, improved on the previous record of 8:04.79 that she set at the Rio de Janeiro Olympics on August 12, 2016.
It was Ledecky’s first world record in a long-course 50m pool since 2018.
The performance capped a stellar week for Ledecky, who posted the second-fastest 1,500m free in history on Wednesday and swam the second-fastest 400m free of her career a day later.
Jillian Cox was second, 19.46sec back on 8:23.58. Claire Weinstein was third in 8:26.06.
Ledecky said she was “fired up” after her 1,500m free, which launched her first elite competition since the Paris Olympics last year.
In Paris she won the 1,500m free and also claimed a fourth straight 800m free gold as she equalled the record for most gold medals won by a woman athlete in any sport.
She owns the 10 fastest 800m free times in history, with Canadian Summer McIntosh the second-fastest performer with her career-best time of 8:09.86.
Since Ledecky burst onto the international scene with her 800m free triumph at the 2012 London Olympics, she has been beaten in the event only once, when McIntosh defeated her at a meeting in Florida in February of last year.
But this week, Ledecky has demonstrated she’s still the woman to beat as she looks toward the World Championships in Singapore July 27-August 3.
The US trials will be held June 3-7 in Indianapolis. (AFP)
