Michael Andrew broke a world record and tied two more in a remarkable single session at the International Swimming Federation (FINA) World Junior Swimming Championships in Indianapolis.
The American first equalled his own junior record of 24.63 seconds to win the 50 metres backstroke at Indiana University Natatorium.
He then improved upon the mark he set in the heats to touch first in the 50m butterfly semi-final in 23.27.
An unprecedented treble was then completed when he won the 50m freestyle in 21.75.
"I just wanted to get under 22, so to do so was amazing," Andrew said about the last victory.
"I'm kind of blown away by it; I didn’t really expect that of myself."
Spain's 100m winner Hugo Gonzalez finished a distant second 0.67 behind in the 50m backstroke.
Kacper Stokowski of Poland finished in third place in 25.38.
Andrew was also in a league of his own in the freestyle final as he touched a full half second clear of Maxime Grousset of France.
Leonardo Deplano of Italy finished a further 0.06 behind in third.
Hungary continued their superb Championships with gold in a world record time in the men's 4x200m freestyle relay.
Richard Marton, Kristof Milak, Balazas Hollo and Nemeth Nandor combined for a time of 7:10.95.
United States finished just one hundredth behind in second in a thrilling race.
Russia claimed bronze in 7:11.39.
Hungary also claimed another gold today as Anja Kesley triumphed in the women's 400m freestyle.
Her winning time of 4:06.72 was 1.61 seconds faster than Delfina Pignatiello of Argentina, the 800m freestyle champion, to reverse the result from the longer event.
Anastasiia Kirpichnikova swam 2.01 seconds behind the Hungarian champion to achieve bronze for Russia.
Rikako Ikee of Japan continued the trend of world records being broken for fun by winning the 50m butterfly in 25.46.
Sara Junevik of Sweden finished 0.72 behind to take silver while American Rebecca Smith earned bronze in 26.22.
Action will conclude with a final day of competition tomorrow.