It's like Michael Phelps never left the pool ...

RIO DE JANEIRO -- On a gorgeous summer evening in Barcelona, Spain, in the summer of 2013, a retired Michael Phelps sat in the press tribune at the World Aquatics Championships frustrated at what was unfolding in the pool down below.

For the second straight major international meet, the United States held the lead in the men's 4x100-meter freestyle relay with 100 meters to go, but were overtaken by France, which both times would go on to win gold. Phelps couldn't stand it. He believed he could have made a difference. He texted coach Bob Bowman about the mistakes Phelps believed the coach had made. But really, that was all he could do. A year earlier, he had retired after the London 2012 Games. He was nothing more than a glorified spectator. He hated it. He thought about a comeback.

Fast forward three years, and there was Phelps on Sunday night, walking onto a world championship-level pool deck for the first time since Barcelona. This time, he was wearing a racing suit. This time, he was swimming the second leg of that same race. And he believed the end result was going to be a gold medal.

Five weeks earlier, Bowman couldn't even picture his star pupil in this position. A mediocre performance at the U.S. Olympic trials had Bowman thinking he should leave Phelps off the relay. But in the following training camp, something began to click. One impressive drill followed another. The great practices began to add up. And in a time trial in Atlanta, Phelps swam a 48.5 from a flat start, forcing Bowman to reconsider.

Phelps would swim the second leg.

When he entered the water Sunday night, following 19-year-old Caleb Dressel, the Americans were in second, three-hundredths of a second behind France. At the 150 turn, the French extended their lead to .13 seconds. But then, in one perfectly executed underwater turn, the greatest swimmer of all time wasn't the spectator, he was the game-changer. When he and the rest of the field resurfaced, the Americans were in the lead -- a lead the Americans wouldn't lose.

Phelps' split of 47.12 was the fastest of his career. At 31 years old. Then he had to wait. For the race's final 90-plus seconds, he watched Ryan Held and Nathan Adrian fight off the rest of the world, standing behind the starting blocks screaming, yelling and throwing his hands into the air. When it was all over, Phelps raised both of his arms high above his head. He screamed in genuine delight. And later smiled as the Olympic gold medal, the 19th of his career, was placed around his neck.

"When I was on the block, I thought my heart was going to explode out of my chest," Phelps said. "I was so hyped and so excited. To hear the stands as loud as it was -- that was wild. I don't know if I've ever heard something like that. It feels good to start the close of my career the way I wanted to."

The gold was the Americans' first in the event since 2008, when Jason Lezak chased down France's Alain Bernard to preserve Phelps' quest for eight gold medals in one Games. It was yet another reminder that some people are just born with something that lifts them to higher levels when it matters most. This was the swimming equivalent of Michael Jordan's jump shot to beat the Utah Jazz, Curt Schilling and his bloody sock carving up the Yankees, or Joe Montana finding John Taylor to win Super Bowl XXIII. It's one of those undefinable intangibles that results in greatness.

This was essentially one of the arguments Adrian gave last week when stating his case to the American captains in each sport to vote for Phelps as the flag-bearer for opening ceremonies here.

"Michael Phelps has set a precedent -- every time we step on the pool deck, we are expected to win gold," Adrian said. "That's what he's done to the Olympic movement."

"He's a pretty good swimmer," Bowman said with a wink. "He knows how to get himself ready. He knows what it's going to take."

Bowman categorized Phelps' underwater turn as the greatest of his career. His split was the fourth-fastest of any of the 32 swimmers in the race and fastest for anyone not swimming an anchor leg. But just as eye-opening was what it might mean for the rest of Phelps' week. On Tuesday, he will swim the preliminary and likely semifinal heats of the 200 butterfly. Then, later this week, he has the 100 fly, 200 individual medley and likely two more relays, the 800 free and medley. That could potentially set Phelps up for as many as six medals.

"Michael usually works this way: When one thing is usually good, everything is good," Bowman said. "So I'm optimistic."

And yet, if you were to ask Phelps or Bowman, they will tell you the medals aren't what is important. Sure, it's great to win, but Phelps has a series of times he wants to hit, something he emailed Bowman about a year ago while they were vacationing in Cabo San Lucas. While Phelps and Bowman refuse to say what those times might be, they have alluded to the goal of Phelps swimming one more personal best before he retires.

It seemed laughable a month ago in Omaha. After Sunday night, not so much.

"He's in a good place now," Bowman said. "He's been as good -- everything I've asked him to do he's been really good at. Way better than trials."

And way better than that frustrated, helpless fan back in Barcelona.

"In my last 400 relay in my career, to get this thing around my neck," Phelps said, holding his gold medal, "it feels really good to get it back."