A record night of the greats in the Paris pool

French poster boy Leon Marchand and U.S. distance dynamo Katie Ledecky made history while the Paris pool saw its first world record on one of the great nights of Olympic swimming on Wednesday.

China's Pan Zhanle ended the programme with another firecracker, the teenager obliterating his own 100 metres freestyle world record to take his country's first swimming gold of the meet.

Before that, Marchand sent sound levels off the scale at the La Defense Arena as he pulled off an unprecedented 200 metres butterfly and breaststroke double -- with a medal ceremony in between.

Both swims were completed in Olympic record time, a remarkable feat in two of the most tiring and demanding disciplines. Until Wednesday, no swimmer had managed to medal in both.

"It was pretty crazy to have the chance to be in the final in both races," he said.

"And then I just loved it, it was huge.

"I've fulfilled a lot of dreams since I've been here. Doing this double was also something I felt capable of, but to really do it in the real world is something else."

With passion, patriotic pride and raw emotion bursting out on all sides, Marchand soaked up the pressure and delivered what even the hype had suggested might be too much.

The winner of Sunday's Individual Medley started with an incredible comeback in the butterfly after Hungarian world record holder and reigning champion Kristof Milak led the first three lengths.

Milak had to settle for silver, with Canada's Ilya Kharun taking bronze.

With the crowd chanting his name at every stroke -- "Leon, Leon" echoing around the arena -- Marchand returned to lead every metre of the breaststroke before touching out in two minutes 05.85 seconds.

Australia's Zac Stubblety-Cook, the 2021 champion in Tokyo, had to settle for silver while Caspar Corbeau of the Netherlands took the bronze.

Australia's Kyle Chalmers was a silver medallist in the men's 100 free behind Pan, with Romania's David Popovici third.

Ledecky also seized her chance to shine, although the win was never really in doubt, as she defended her 1,500 freestyle title for a record-equalling eighth gold.

The American now shares the record for most Olympic golds in women's swimming with compatriot Jenny Thompson, who won eight relay titles over three Olympics from 1992-2000.

Her 12th medal matched the all-time record shared by Thompson, Americans Dara Torres and Natalie Coughlin, and Australian Emma McKeon.

She also became the first female swimmer to stand at the top of the podium at four Olympics, something only male compatriots Michael Phelps and Ryan Lochte have managed.

Another familiar name also returned to the top when evergreen Swede Sarah Sjostrom won the women's blue riband 100 freestyle -- a race the sprint queen only decided to enter late in the day.

"I didn't think I would swim the 100 free," the 30-year-old told reporters after reeling in American silver medallist Torri Huske and Hong Kong's bronze-winner Siobhan Haughey.

"I was like...'I want to do the 50, I want to rest until the 50', and he (her coach) was like, 'No way, you need to go out there and see what you can do, no matter the outcome'."

Canada's Summer McIntosh led the women's 200 butterfly semi-finals, ahead of Regan Smith of the United States and China's Olympic record holder Zhang Yufei.

American Kate Douglass was fastest in the women's 200 breaststroke semis, ahead of South Africa's 100 champion Tatjana Smith.

American Ryan Murphy, the 2016 Olympic champion, failed to qualify for the men's 200 backstroke final after winning the 100 bronze on Monday.