Leon Marchand is likely to be one of the stars of the Games, not just because he's a local boy, but because the 22-year-old, who broke Michael Phelps' world record in the 400 metres individual medley last year, is in phenomenal form.

His anticipated starring role at the Olympics is being further cemented by great performances such as the one he produced in the 100m butterfly at the Speedo Grand Challenge meeting in California on Saturday.

The Toulouse-born youngster clocked 52.56 seconds to finish more than a second ahead of American Billy Picht (53.71).

It was his third win in two days at the meeting in Irvine, California, which takes place just over two weeks before the French Championships from 11-16 June.

Marchand completed an impressive double in the 200m individual medley and 100m breaststroke on Friday.

The five-time world champion also won the 200m individual medley in 1:55.74, less than a second off the European record he set when winning gold at the 2023 World Championships in Fukuoka.

It was a solid performance, less than 20 minutes after winning the breaststroke in 59.06 seconds, from someone who has the challenge of being the host nation's great hope when he takes to the pool at Paris La Défense Arena in Nanterre from 27 July to 4 August.

Marchand, who enjoyed a stellar collegiate career in the United States under the tutelage of former Phelps mentor Bob Bowman, will head into his home Olympicsas the favourite in both medleys and the 200 butterfly, all of which he won at last year's World Championships.