LONDON Michael Phelps’ joy started to spill over while he was still in the water, a few strokes from the finish in the men’s 4-by-200 freestyle Olympic relay Tuesday.

“I started smiling with 20 meters to go,” Phelps said. “It’s the first time I’ve ever done that in a race.”

It was a night for firsts, so the underwater smile was fitting. Phelps won a gold medal in that relay with his teammates – one of them was Charlotte’s Ricky Berens, who minutes after the race suddenly retired from swimming at age 24.

These will be Phelps’ last Olympics, too. The relay gold earned him his 19th career Olympic medal, which surpassed Soviet gymnast Larissa Latynina’s all-time record of 18.

“I’m happy with my three Olympic medals,” Berens said. “Nineteen has to be a pretty good feeling.”

There will likely be more for Phelps, who has three events left.

For my money, Phelps is the greatest Olympic athlete ever. He has shown a bit of vulnerability at the 2012 Summer Games, finishing fourth, second, second and first in his four events. But that means he already has three medals. Those go nicely with the 16 medals he won – 14 of them gold – in previous Olympics.

“Michael has had three amazing Olympics in a row,” U.S. swim coach Gregg Troy said, shaking his head. “Any athlete would be very happy to have one of those. And he’s had three.”

Phelps’ 18th medal had come an hour before the relay began and had once again showed his human side.

He led the 200 butterfly – his best individual event – for the first 195 meters. But South Africa’s Chad Le Clos was closing fast and went with a full stroke at the end while Phelps tried to glide in to the wall. Le Clos out-touched Phelps for the gold.

It seemed like some sort of karmic payback for Phelps’ most famous race of the 2008 Olympics, when he did almost exactly the same thing in the 100 butterfly to snatch the gold medal away from Serbia’s Milorad Cavic at the last millisecond.

“I was on the receiving end of getting touched out,” Phelps said, shaking his head. “Sure, I was upset.”

Le Clos was nearly in shock at the win. “Phelps is my hero and I love the guy,” he said. “You don’t understand what this means to me. This is the greatest moment of my life.”

Phelps, meanwhile, was angry.

“And a mad Michael Phelps is a good guy to have on your side on a relay,” Berens said.

To maximize his time between events, the U.S. put Phelps on the anchor leg of the 4-by-200 relay. It’s an event the U.S. almost always wins – it had done so in three of the past four Olympics.

“I told those guys I wanted a big lead,” Phelps said.

He got one. Ryan Lochte, shaking off two straight iffy performances the previous two nights, led off and put the U.S. in first place by a body length.

“I had a pretty rough couple of days, but today I woke up and felt good,” Lochte said.

Conor Dwyer and Berens stretched the lead to almost three body lengths and three seconds when they swam their legs of the race.

By the time Phelps dove into the pool, he had what NASCAR drivers like to call “clean air” in front of him, except this time it was clean water. Phelps was comfortably ahead the whole way, even with France swimming star Yannick Agnel giving chase. The U.S. ended up winning by 3.07 seconds with a time of 6 minutes, 59.70 seconds, but did not break the world record it also holds. France was second and China third.

Phelps huddled his relay teammates together after the race and thanked them for helping him set the medal record. He gave the flowers every medal winner gets to his mother, as is his personal tradition. And he made no secret later of how much the medal record meant to him.

“Being able to do something no one has ever done before, that’s what I’ve always said I wanted to do,” Phelps said. He also seemed less stressed after the race than he had for the first several days of the meet.

“The first couple of days I was super uptight,” Phelps said. “The last couple of days I’ve been laughing all the time, joking, having fun. That’s what I said I wanted to do in the beginning, and that’s what I’m going to do the rest of the week.”

At 27, Phelps likely could stay good enough to make the Olympic team again in 2016. He has said repeatedly he has no interest in doing that, although his mother recently told “60 Minutes” she would like him to do so.

Phelps’ medal total seems staggering, given that many athletes struggle for years to win a single Olympic medal. He does benefit from being in a sport – like gymnastics and track and field – where multiple medals are available in every Olympics.

Still, 19 medals?! Isn’t that an untouchable record?

“Nothing is untouchable,” Phelps said, and he walked out into the London night, still smiling.