When it was done, there wasn't that water-pounding celebration we've seen so many times from Phelps - just a slight smile as he hung on the lane rope, gazing up at the stands and soaking it all in.
"Going into every [ready] room, I said it's my last semifinal or my last prelim," Phelps said, reflecting on a busy day that included a morning swim, then two more races in the evening. "We're kind of chalking up all the lasts of certain things."
As he stepped on the medal podium - that familiar top rung - Phelps' eyes were glassy and he whispered something to Lochte. Then, staring up at the U.S. flag while the nation anthem played, he bit his lip and seemed to be struggling to hold back the tears.
Phelps has never been too revealing with his emotions away from the pool. But, with just 2 days to go in his swimming career, there's a definite chink in the facade.
He's starting to look as human out of the water as he is superhuman in it.
"To be able to win the gold medal and be the first to threepeat, it means something," said Phelps, whose first gold in London was swimming the anchor on the 4 x 200 freestyle relay. "It's pretty special and something that I'm very happy for."
A farewell games that started as a bit of a disappointment is definitely looking up. He's now won two golds and two silvers in five races - not the eight golds in eight races in China, but a more-than-fitting capper to a brilliant career that still has two more races to go: the 100 butterfly Friday and the 4 x 100 medley relay Saturday.
Lochte settled for silver in 1:54.90 and Hungary's Laszlo Cseh took the bronze, well behind the Americans in 1:56.22.
"Always chasing Mike and Ryan," Cseh moaned. "It's really hard because those two swimmers are really good."
Lochte went through the same warm-down routine in the diving pool as Phelps, trying to pull off an impressive double 31 minutes apart. He came up short in both races, fading to bronze in the 200 backstroke behind fellow American Tyler Clary, then touching after Phelps in the medley.
Lochte shook hands with his rival before crawling out of the pool for the last time at these games, though he intends to keep on competing through the Rio Games in 2016. In a symbolic gesture, he tossed his cap and goggles into the crowd, his work done. His final tally: two golds, two silvers, one bronze and a fourth-place finish - impressive, but undoubtedly shy of what he had predicted would be "my time."
This time still belongs the Phelps.
""Yeah, I wanted to get all golds in my events, but you know it didn't happen,'' Lochte said. "I'm going to have to live with that and move on and learn from it, and try not to make the same mistakes in the next 4 years.''
Among the women, American Rebecca Soni made quite a splash, too. Tearing through the water in her favorite pink suit, Soni set her second world record in as many days to defend her Olympic title in the 200 breaststroke. She finished in 2:19.59, breaking her own mark of 2:20.00 set in the semifinals.
"I'm so happy," Soni said. "I can't believe I did it."
Ranomi Kromowidjojo carried on the Dutch tradition of producing top sprinters and prevented a red, white and blue sweep of the night, taking the 100 freestyle in an Olympic-record 53.00.
American teenager Missy Franklin got off to a terrible start - she was last at the turn - and couldn't rally. She finished fifth, two-tenths off the podium. The other U.S. swimmer, Jessica Hardy, finished last in the eight-woman field.
