World record holder Leon Marchand stormed to 400m individual medley gold while Adam Peaty was upset in the 100m breaststroke final.

Leon Marchand surged to France’s first Olympic swimming gold since 2012, obliterating the field to clock the second-fastest 400m individual medley time ever.

The 22-year-old led off strongly on Sunday and never looked back, touching in 4mins 02.95secs, nearly six seconds clear of Japan’s Tomoyuki Matsushita in second, with American Carson Foster third.

Marchand was the heavy favourite after demolishing Michael Phelps’s 15-year-old world record in a phenomenal 4:02.50 swim last year.

His performance at a raucous La Defense Arena in Paris was a new Olympic record.

With American defending champion Chase Kalisz failing to reach the final and with the packed crowd roaring him on, Marchand was half a body length clear after the opening butterfly leg.

But it was a sensational backstroke 100m that left his rivals trailing.

Trained by Phelps’s old coach Bob Bowman, Marchand seized a win that made him France’s first pool gold medallist since the London Games, when they won four.

At the 2021 Olympics, France took home just one swimming medal, Florent Manaudou’s silver from the 50m free.

Marchand, a five-time world champion, will also swim the 200m medley and 200m butterfly as he builds on his burgeoning reputation.

No three-peats

Italy’s Nicolo Martinenghi won the men’s 100m breaststroke gold at the Paris Olympics and denied Adam Peaty a ‘three-peat’ third successive win.

Peaty, bidding to become only the second male swimmer after retired US great Phelps to win the same title at three successive Games, took silver together with Nic Fink of the USA.

Their time of 59.05 was just 0.02 of a second slower than Martinenghi’s.

Team USA 1-2 in women’s 100m fly

Torri Huske stunned American teammate and world record holder Gretchen Walsh to clinch the women’s 100m butterfly gold medal on Sunday.

Walsh turned first but Huske came home strongly to touch in 55.59secs, with Walsh second in 55.63 and China’s Zhang Yufei taking bronze (56.21).

Huske’s win continued a sequence of the event never having had a repeat winner since it was first held in 1956. Canada’s reigning champion Maggie Mac Neil finished fifth.