Chinese 12-year-old Yu Zidi was narrowly fourth in 2:06.43.

McIntosh, a three-time Olympic gold medallist and former world record-holder in the event, sliced more than a second off the previous world record of 3:55.38 set by Australian Ariarne Titmus at the 2023 World Championships in Fukuoka, Japan.

The 17-year-old swimmer did it in an Olympic record time of two minutes 06.56 seconds, taking down the 2016 record of 2:06.58 set by Hungary's Katinka Hosszu, to complete a medley double after winning the 400 last Monday.

The 17-year-old hit the wall in an Olympic record 2min 03.03sec ahead of America's Regan Smith (2:03.84) and Chinese defending champion Zhang Yufei (2:05.09

World record-holder McIntosh produced a dominant 400m medley swim in Paris, clocking the fourth-fastest time ever.