For the first time in more than a century, Britain claimed a relay gold at the Olympic pool.
The United States, shockingly, didn't even make the podium.
A dynamic quartet carried the British to a dominating victory in the men's 4x200 metre freestyle relay on Wednesday.
Tom Dean, the 200 free gold medalist led off and 200 silver medalist Duncan Scott swam the anchor leg. James Guy - now a three-time Olympic medallist - and 18-year-old Matthew Richards took the middle legs.
"This has been years in the making," Dean said. "We've been getting stronger and stronger."
The British just missed the world record with a winning time of six minutes 58.58 seconds.
The Americans set the record at 6:58.55 in rubberised suits at the 2009 world championships in Rome.
"We were so close to the world record in the end," Scott said. "If anything, I'm a bit gutted."
Imagine how the Americans must've been feeling.
For the first time in its proud swimming history, the US failed to win a relay medal when entering an event.
Kieran Smith, Drew Kibler, Zach Apple and Townley Haas finished in 7:03.24, not only far behind Britain but also trailing Russia and Australia, who claimed the silver and bronze respectively.
The result outraged Michael Phelps, who was part of so many winning relay teams during his career and is now at the Tokyo Aquatics Centre as a television commentator.
Phelps criticised the American coaches for not including Caeleb Dressel on the relay, even though it's not clear if he had any desire to add another event to his busy schedule.
"It's shocking," Phelps said in an interview on NBC. "You know, in my opinion, he's probably the best 200 freestyler in the world. He can probably put up one of the best times that we've seen. Leaving him off that relay, to me, I think makes it a lot harder to win the gold medal."
Without him, the American not only didn't win gold, they were shut out altogether.
The only other times that happened were at 1912 Stockholm Games, when the Americans didn't enter a team in the women's 4x100 free relay, and the 1980 Moscow Games, when they didn't show up at all because the Soviet invasion of Afghanistan.
Otherwise, the US had been 94 of 94 in the relays - not all of them wins, of course, but medals at least.
Make it 94 of 95.
The British made their own bit of history.
It was their first relay gold since that aforementioned women's 4x100 free in 1912, with their only victory coming in the men's 4x200 free relay at the first London Games in 1908.
Australian Associated Press