RIO DE JANEIRO – This should be stressful, because he is 31 and no longer technically in what would rank as the best racing form of his life. That was years ago, when his body would respond on command. Throttle back, no problem. The gas was always there.

How, then, did Michael Phelps end up hanging on the lane line, in an Olympic final no less, waiting for the rest of the field to finish? He touched the wall and won the 200-meter individual medley Thursday night at Olympic Aquatics Center, and when he did, a race whose result might have been considered in question just two minutes earlier was instead etched in stone.

The next finisher, Japan’s Kosuke Hagino, touched 1.95 seconds after Phelps. In the course of your day, that’s a sip of coffee. In swimming, it’s a long, lazy summer afternoon. Phelps could have knitted a sweater or FaceTimed his infant son. Either way, he had a shockingly easy gold. And because the numbers are an essential part of who he is and what he is doing here, we offer them again: four golds in Rio, 22 golds in his career, 26 medals overall. The gap between that total and the next-closest Olympian in history is something like the gap between Phelps and the field Thursday night, because Russian gymnast Larisa Latynina, who Phelps blew past in London four years ago, is second with 18 Olympic medals.

“I mean, it’s Michael,” said Ryan Lochte, a 12-time Olympic medalist himself. “Nothing surprises me anymore with that guy.”

Phelps’s performance came on the latest remarkable night for the U.S. swim team, which is outperforming most countries in Rio. Simone Manuel became the first African-American ever to win an Olympic medal in an individual swimming event, storming to gold in the 100 freestyle. And Ryan Murphy, a young Floridian who swims at Cal, won his second gold of the Rio Games, this in the 200-meter backstroke.

Because this is Phelps’ final Olympics – at least, what he says is his final Olympics – it was appropriate that two young athletes who might take his efforts to expand swimming and run . . . er, swim with them. The significance of Manuel’s victory, in an Olympic record 52.70 seconds that was tied by Canadian teenager Penny Oleksiak – meaning they both received golds – was apparent immediately. Even at 20, Manuel knew there were young African-American girls watching, and that mattered.

“Hopefully it will get them inspired,” Manuel said. “The gold medal wasn’t just for me. It was for people who have came before me and inspired me to stay in this sport, and for people who believe that they can’t do it. I hope that I’m an inspiration to others to get out there and try swimming. They might be pretty good at it.”

So, then, the Phelps revolution of the sport continued in myriad ways as he closes his career. That he crushed the 200 IM on such a night also seemed to fit. Though he first made the Olympics in the 200 butterfly, back when he was a floppy-eared, gangly-armed 15-year-old, it is the two events he swam Thursday night in which he had never lost gold at the Games. The final of the 100-meter butterfly — presumably the last individual race of Phelps’s career – comes Friday night, and he positioned himself fifth by swimming a semifinal heat of 51.58 seconds.

By now, Phelps has put his fingerprints all over each event he swims at the Games. But in no event does he have such a personal history with a single athlete as he does with Lochte in the 200 IM, a Bird-vs.-Magic, Manning-vs.-Brady dynamic that has helped push each to widespread recognition in the U.S. Swim fans know the event, one pool length each of the butterfly, backstroke, breaststroke and freestyle. People walking down the street know only the characters that swim it, and that they always seem to be within an arm’s length of each other.

Lochte broke Phelps’s world record at the 2009 world championships in Rome, then dropped it to its current level – 1:54.00 – two years later at the world championships in Shanghai. In that race, he beat Phelps by 16 hundredths of a second, and those two swims still stand as the first- and third-fastest times ever posted in the event.

A rich history, sure. But consider that after U.S. trials earlier this summer, Phelps and Lochte actually owned the top 15 times ever. Hagino was the next fastest in history, a 1:55.07 that was pertinent Thursday night not because of the number, which Phelps and Lochte would have spit at in their primes, but because it came this year.

Entering the night, the culmination of that rivalry was enough to overshadow the night’s three other major developments – Murphy’s gold in the 200 back, an event in which the U.S. has now won at six straight Olympics, Manuel’s groundbreaking gold, and the end of these Games for Missy Franklin, which was somehow simultaneously stunning and predictable.

“I’m someone who is never really satisfied with my results,” Murphy said, and that points to his spot, at age 20, as someone who might fill in for Phelps in Games to come.

Franklin, swimming just before Phelps, was merely in the semifinal of the 200 backstroke – an event she won four years ago in London. But the Missy Franklin here isn’t the Missy Franklin there. She finished 14th of 16 swimmers over two heats, and didn’t advance.

“It’s the story of my week,” Franklin said through tears. “. . . For some reason, it’s just not there right now. I wish I had an excuse, but I don’t, and I’m not going to make up one.”

So it was left to Phelps and Lochte, a race that materialized only over the first 100 meters. After the backstroke leg, Lochte actually led by a hundredth. He is not an extraordinary breast stroker, but he seized the race on that length of the pool, swimming it in 33.51 seconds. But it was his freestyle leg that was extraordinary, and by the time he was 20 meters off the wall following his turn, he could all but coast. He touched in 1:54.66, his fastest time since the London Olympics, the eighth-fastest ever.

Afterward, he stood on the medal stand – they ought to put a couch up there for him – and listened to the “Star-Spangled Banner.” Two nights ago, following the 200 butterfly win, he laughed. This time, he choked back tears. He is winning races in all manner of ways. Might as well let the reactions cover everything in history as well.

Murphy completed a backstroke double and extended a U.S. winning streak, adding the Olympic men’s 200-meter gold to the 100 title he won earlier in the week.

The U.S. men have now won the event for six successive Olympics dating back to Atlanta in 1996.

World champion Mitch Larkin, who had hoped to become only the second Australian to win a backstroke gold and the first since 1960, took the silver medal while Russian Evgeny Rylov clinched bronze.

“There’s a lot of pressure. Unfortunately Ryan came over the top of me,” said Larkin.

Murphy, a 21-year-old first time Olympian, trailed Larkin over the first 50 meters but took the lead after the turn and stayed ahead to touch out in one minute, 53.62 seconds — the fastest time of the year.

He will be heavily fancied to take his third medal of the Games in Saturday’s medley relay, having set an Olympic record in winning the 100 backstroke.

“That one was very painful but I wanted it bad. The 100 backstroke comes more naturally for me,” said Murphy.

“The 200 back is an event I really have to dig deep for. This medal means a little more to me.”

Larkin finished in 1:53.96, beating world junior champion Rylov (1:53.97) by the closest of margins.

Tyler Clary, the gold medallist at London 2012, was unable to defend his title after failing to be selected at the U.S. trials.

In the 50-meter men’s freestyle heats, Olympic champion Florent Manaudou qualified fastest for Friday’s final.

In a fast and furious burst of whitewater, France’s Manaudou clocked 21.32 seconds, narrowly edging out Ukraine’s Andrii Govorov and Anthony Ervin of the United States, who swam in the second semifinal and finished in a dead heat in 21.46 seconds.

Nathan Adrian of the United States, Benjamin Proud of Britain, Bruno Fratus of Brazil, Simonas Bilis of Lithuania and Brad Tandy of South Africa rounded out the qualifiers.

Australia’s Cameron McEvoy, who had qualified for the Games with the second fastest time in the world this year with a time of 21.44 seconds at the Australian championships, was 11th fastest in 21.89 seconds.

Earlier, Japan’s Rie Kaneto won the Olympic gold medal in the women’s 200-meter breaststroke, edging out controversial Russian Yulia Efimova who won her second silver of the Games.

Shi Jinglin of China took the bronze.

In the 800-meter women’s freestyle heats, Katie Ledecky put another golden, and late, night behind her and focused on winning a fourth title at the Rio Games in her favorite event.

The 19-year-old did not push too hard in the heats after anchoring the U.S. to victory in the 4x200m freestyle relay late on Wednesday, but still set an Olympic record time of eight minutes 12.86 seconds.

Her closest rival, Hungary’s Boglarka Kapas, was nearly seven seconds slower in 8:19.43 with Britain’s Jazz Carlin third in 8:19.67.

“(Coach) Bruce (Gemmell) just told me to think about my rhythm the first 200 and then he didn’t give any other instructions,” said the world record holder and defending champion who has become unbeatable at the distance.

“Well, he told me not to take a hard stroke so I tried not to.”

Ledecky said she had got to bed at about 3.15 a.m and, not being one for sleeping in, was up again at about 9 a.m.

“I’m happy. I get tonight off, tomorrow morning off and get to race again,” she said

Ledecky has already won the 200m and 400m freestyle and is going for the individual golden triple. She also has the 4×200 relay gold and a 4×100 silver.

Spain’s 2012 silver medallist Mireia Belmonte, who won the 200m butterfly on Wednesday, also had a quick turnaround and was back in action in an earlier 800m heat, securing the last slot for the final in 8:25.55.

That left New Zealand’s 2015 world championships silver medallist Lauren Boyle out in the cold after she finished ninth.

Before the women’s longest distance, the men began their shortest with Ukraine’s Andrii Govorov fastest in the 50m freestyle heats.

U.S. teammates Nathan Adrian and Anthony Ervin were second and third.

In the women’s 200m backstroke, Hungary’s Katinka Hosszu remained on course for her fourth individual gold of the Games after leading the way in two minutes 06.09 seconds, ahead of Canada’s Hillary Caldwell.

Maya DiRado of the United States was third fastest as she also chases her fourth medal in Rio.