TOKYO — By the time an American swimmer named Townley Haas touched his hand to the wall Wednesday morning at Tokyo Aquatics Centre, Britain’s Duncan Scott was celebrating in the pool, about to pull his cap from his head and climb onto the deck to embrace his teammates. The Tokyo Olympics are turning into a fabulous event for British swimmers, and here was something for an entire country to enjoy: gold, in the men’s 4x200-meter relay.

What Haas and his American teammates experienced is something that’s completely unprecedented — and because of that, comes with questions. Before Haas finished his anchor leg — giving the United States a time of 7 minutes, 2.43 seconds — the Russian Olympic Committee team had finished more than six-tenths of a second ahead of him. Australia, likewise, got to the wall three-hundredths behind the Russians.

And so, the relay medals — gold to the Brits, silver to the Russians, bronze to the Australians — did not go to Americans for the first time in Olympic history. That includes men. That includes women. It includes them all, and raises the question: Where was Caeleb Dressel?

“I think his actions indicate he wants to be on that thing and wants to help us win a medal,” said Dave Durden, head coach of the U.S. men’s swim team.

Which means, then, the coaches left him off — and the result was unprecedented, a gut-punch to a proud American team.

“In the moment, absolutely,” Durden said. “But like any little gut punch we take — and we’ve taken some blows before — stand back up, get on to our next session and get going.”

Dressel, a gold medal favorite here in sprints, is not a 200 freestyler by trade. But he is a star, and he is not a novice in the event. Before these Olympics, he had said he was very interested in swimming a leg of the 4x200. Yet before Wednesday morning’s session, the American coaches submitted a lineup with the following swimmers: Kieran Smith, Drew Kibler, Zach Apple and Haas. Of those, only Haas had experience in an Olympic final, swimming the second leg of the gold-medal-winning team in 2016.

The men’s 4x200 free relay dates from 1908. In 24 previous attempts, the U.S. team had never failed to medal, and 17 of those were gold. That includes the past four Olympics, when two absolute stars — Michael Phelps, the greatest athlete the sport has ever seen, and Ryan Lochte, his longtime foil — pushed the Americans to victories in Athens, Beijing, London and Rio de Janeiro.

But this was always to be a transitional Olympics for the American male swimmers. Phelps is here but is either cheering on his former teammates from the stands or contributing to NBC’s analysis. Lochte tried and failed to make the team at 36.

But the Americans still have Dressel, and he opened Wednesday morning’s session by swimming a smooth 100 free, winning his semifinal heat in 47.23 seconds — the fastest time in the world this year when he got out of the pool, but good for just the second seed in Thursday’s final because the ROC’s Kliment Kolesnikov went 47.11 in the second semi.

Yet surprisingly, that was Dressel’s only swim of the morning. Last month at the U.S. trials, he swam a preliminary heat of the 200 free, setting his personal best of 1:46.63. He then scratched out of the event before the semifinals, and the intention seemed clear: He posted the time to put himself in the mix for the 4x200 relay at the Games.

“Like all our relays, we have spent a lot of time chatting about this,” Durden said. “We’ve spent a lot of time looking at schedules, looking at individual schedules, seeing how it’s going to impact the current session, impact the other sessions that are coming up. …

“We just felt it was best for Team USA, best for our men’s team, best for Caeleb to put us in the position to win the most medals throughout this meet to not have him on that 800 free relay.”

The calculus: Given that the bulk of Dressel’s program remains, it would be best to sacrifice the relay for success later in the week. Still ahead for Dressel: finals in the 100 free, 100 butterfly, 50 free and, in all likelihood, two relays — the 4x100 free and the freestyle leg of the medley relay.

Plus, even had Dressel been included, the United States wasn’t assured of the medal stand. Only Smith qualified for the final of the 200 free, and he finished a distant sixth in 1:45.12 — nine-tenths of a second behind gold medalist Tom Dean of Britain, a few ticks off his personal best in the event.

But consider the event this way: Apple, swimming third, struggled badly. Kibler had put the Americans narrowly behind at the midway point of the race, and Apple actually overtook Britain’s Matthew Richards at the 100-meter mark of his leg.

But from there, he about sank. Over the final two lengths of the pool, Apple was passed by four teams, three in the last 50 meters alone. The Americans’ medal position evaporated. Of the dozen swimmers for Britain, the ROC and Australia, none turned in a leg slower than 1:46. Apple’s split: 1:47.31.

“We felt good about it going into this morning,” Durden said. “It doesn’t change who Zach is as a swimmer, because that guy is rock-solid on relays. He just had a bad swim. And that is going to happen. We all have bad swims here and there.”

This, though, isn’t here or there. It’s at the Olympics. The numbers are stark: Had Dressel swum and merely matched his time from trials, the streak would have been alive. It would have been enough for silver.

“When it goes well, you look like you know what you’re doing,” Durden said. “When it doesn’t go well, it looks like you don’t know what you’re doing.”

The Americans’ medals Wednesday, then, came from not only from Katie Ledecky’s victory in the 1,500 freestyle, and not only from red-white-and-blue teammates — but from navy-blue-and-orange teammates. Abby Walsh is from Nashville and Kate Douglass is from Pelham, N.Y., but they swim together at the University of Virginia — and in Charlottesville, that was enough to promote a watch party at Scott Stadium.

“The support from them has been amazing,” Douglass said.

Wednesday morning, the two swam in adjacent lanes at Tokyo Aquatic Center for the final of the women’s 200 individual medley — Douglass in lane 4 as the top seed, Walsh to her right in lane 3, having posted the third-best time in semifinals.

Both showed up. When they made the final turn — when breaststroke turned to freestyle, and 50 meters remained — Walsh led and Douglass was fourth. Over that one length of the pool, Walsh was passed by Japan’s Yui Ohashi, who swam a blistering leg of 30.75 seconds. But she hung on for silver, just as Douglass moved up to third, passing Britain’s Abbie Wood.

When they saw the results, Walsh and Douglass embraced over the lane line, two Cavaliers half a world away from Charlottesville, each with a medal to be placed around their necks.

“We just kind of put our hearts on the line, and it worked out,” Walsh said.

For the first time, it didn’t work out for an American relay team. That brought questions for the men who participated — and about the one who did not.