Although Michael Phelps retired seven years ago, his legacy has continued to tower over swimming.

But on Saturday, Phelps鈥 last remaining world record was smashed by 21-year-old Leon Marchand at the World Aquatics Championships in Fukuoka, Japan, as the Frenchman completed the 400 meters individual medley in 4:02.50, shaving an enormous 1.34 seconds off Phelps鈥 previous mark.

鈥淭hat was insane, one of the most painful things I鈥檝e done. It was amazing to do it here and the time is crazy,鈥 Marchand said afterwards, according to the Olympics鈥 official website, 鈥淭he best is yet to come.鈥

Marchand was just six years old when Phelps set the previous world record in the discipline, at the 2008 Beijing Olympics, and he was presented with the gold medal afterwards by the legendary American swimmer.

Phelps himself had held the world record for almost 21 years, setting a series of increasingly faster times during his stint as the world鈥檚 most dominant swimmer.

鈥淚t鈥檚 excellent, I train everyday for that,鈥 Marchand added. 鈥淚鈥檓 two seconds faster than my previous record, I beat the world record, it鈥檚 amazing鈥 I don鈥檛 know what to say, I鈥檓 so happy.鈥

The 21-year-old was under Phelps鈥 world record pace for the entirety of his swim, eventually finishing more than four seconds ahead of the USA鈥檚 Carson Foster in second and almost seven seconds ahead of Japan鈥檚 Seto Daiya in third, as he secured his third ever gold medal at the world championships.

Meanwhile Australia鈥檚 Ariarne Titmus set a world record in the women鈥檚 400 meter freestyle with a time of 3:55.38, so blistering that she held off Katie Ledecky in second place.