The machine-like swimmer, who seemed to run on motor rather than muscle and scooped up medals by the handful, had become an actual human being, one whose less than golden perfection made the victories that much sweeter when they came as they did on Tuesday night.
"This has been an amazing ride," Phelps said almost pensively Tuesday night, when he won the 19th medal that made him the most-decorated Olympic athlete ever.
"It was a cool feeling. I'm sure I'll be able to put it more in words once we get through the meet and then probably down the road," Phelps said of how on Tuesday he first tied and then surpassed the 48-year-old record for most Olympic medals previously held by Soviet-era gymnast Larisa Latynina.
The race that allowed him to surpass Latynina's 18 medals, the 4 X 200-meter freestyle relay he anchored, was won quite easily. But what perhaps was most impressive was that it came about an hour after he suffered a heartbreaking, second-place finish by .05 of a second in his signature event, the 200-meter butterfly.
"I have never been prouder of him," his longtime coach Bob Bowman said, his eyes reddened from the emotion of the night, seeing how the now 27-year-old Baltimore swimmer swallowed his anger and disappointment and rallied to the next race. The younger Phelps, Bowman said, may not have been able to do that.
No one has ever dominated the Games as Phelps has, become its veritable face really, and yet on this night he seemed eager to talk about other swimmers. He has always said that his primary goal has been to elevate his sport, and it is clear that in many ways he has done that. There are swimmers who, indeed, wanted to be like Mike and they are now his teammates, and competitors.
The first thing Phelps said after winning the relay gold medal Tuesday night, huddled on the pool deck with the three other swimmers, was thank you.
"I thanked them for being able to allow me to have this moment," he said. When they gathered on the medal platform, he had one more message for them.
""Sorry boys, I'm not going to be singing this with you guys," he said of the anthem that would be played. "There are too many emotions that are going on, I'm never going to be able to get a word out. I tried to hold myself together as much as I could, my eyes were getting watery."
Part of that emotion surely comes from seeing that the end is in sight. Three more events and he will close out a swimming career that surely won't be duplicated or surpassed soon -- if ever. Already, he has evolved into something of its elder stateman, the mentor to not just his own teammates, but all swimmers, everywhere.
Perhaps the most-touching part of an extraordinary night was the way Phelps, having just been beaten by South African swimmer Chad Le Clos, took the 20-year-old under his wing to navigate the medal ceremony. Le Clos, who as a 12-year-old watched Phelps win his first six gold medals and carries videos of his many races on his laptop, said that during the dream-like state he was in, Phelps told him to take it all in.
"Live the moment," he said Phelps told him as the older swimmer led him on the victory lap medalists take, showing him where to stop for the photographers and how to hold his new medal close to his face. "Enjoy it. It's special."
"Coming from him, it is special," Le Clos said.
Le Clos said the lessons he learned having watched Phelps' races "a million times" came to bear on this night, particularly the 100-meter butterfly race in the Beijing Games in which the Baltimore swimmer out-touched Milorad Cavic by a fingernail.
"I actually thought I was Michael," Le Clos said of what went through his mind in the homestretch of Tuesday night's race. "I remembered how he did it... The last 25 meters came in slow-motion."
Before he left his press conference, Le Clos had one last thing to say.
"I want to say congratulations to Michael and his team," he said, "for achieving something great."
The 4 X 200 free relay, after the surprising falters earlier in these Games by Phelps and Ryan Lochte, was refreshingly never in doubt. There would be no sneaking up in the last leg by the French swimmer Yannick Agnel, who grabbed victory in the 4 X 100 free relay from Lochte on Sunday.