Caeleb Dressel captured three gold medals inside 90 sensational minutes on Saturday, taking his personal haul at the world swimming championships to six with a seventh on the cards on Sunday.
Dressel capped his stunning display by helping the United States to a world record in the mixed 4x100m freestyle relay having kicked off his historic night by winning the men's 50m freestyle and 100m butterfly golds in the space of half an hour.
He completed the hat-trick by swimming the opening leg of the relay before Simone Manuel touched the wall at three minutes, 19.60 seconds to seal America's win.
It's thought to be the first time a USA swimmer has won three golds medals in one day at a world championships.
"I haven't had much time to think tonight," said the 20-year-old.
"It's back-to-back events, it's physically demanding and mentally it's even more straining."
The relay time shaved more than three seconds off the previous record the US team set two years ago in Kazan.
The Netherlands took silver at 2.21 secs back while Canada claimed bronze at 3.95.
The championships close on Sunday with the USA well ahead in the medal table with 14 golds, 10 silvers and seven bronzes in the swimming events.
Dressel has now won six golds in Budapest.
He has three individuals titles, including the 100m freestyle, plus victories for the USA in the men's 4x100m freestyle, mixed 4x100m medley and mixed 4x100m freestyle relays.
He could win a seventh gold in the men's 4x100m medley relay on Sunday.
"I have 24 hours to my next swim, so I'll give myself 30 minutes tonight to let it sink in a bit and then it's time to refocus for the next event tomorrow," said Dressel.