Usain Bolt wins the 100 meters in 9.81 seconds, his third straight gold in the event. Justin Gatlin won silver. (Jonathan Newton/The Washington Post)

The first time he became an Olympic star. The second time a track legend. Winning his third straight 100-meter final Sunday night — a feat no man or woman had previously accomplished and few even fathomed — only raised the bar. As he usually does, Usain Bolt set it to sights only he can see.

“Somebody said I can become immortal,” Bolt said after his latest win. “Two more medals to go, and I can sign off. Immortal.”

The 100 has long been one of the Olympics’ signature events, featuring athletic royalty like Jesse Owens and Carl Lewis. But with his electric win Sunday night at Olympic Stadium, Bolt became the only person to capture the Olympic 100-meter title three times.

Bolt won gold at these Rio Games with a time of 9.81 seconds, besting American Justin Gatlin by 0.08 seconds. Canada’s Andre De Grasse took bronze with a personal best of 9.91.

The 29-year-old Bolt came to these Olympics intent on winning three more gold medals before walking away. He already had defined this era of track, helping his country swathe the sprints in green and yellow. Bolt’s win came just one day after fellow Jamaican Elaine Thompson won the women’s 100, and Jamaicans have now won both the men’s and women’s 100 at the past three Olympics.

University of Virginia physics professor Lou Bloomfield explains some of the fundamental forces at work in Olympic sprinting, and how runners use sprinting blocks to get ahead. (Thomas Johnson,Julio Negron,Danielle Kunitz,Dani Johnson,Osman Malik/The Washington Post)

While the first week of these Olympics was a celebration of Michael Phelps, the most decorated Olympian ever, the second week is for its biggest showman, the fastest man on this planet and, as best as scientists can tell, any other one as well. His goal at these Rio Games was to win three more golds and hang up his running shoes with nine total.

“I want to set myself apart from everybody else, and this is the Olympics I have to do it,” he said.

Even before Bolt took the track for Sunday’s final, the crowd was treated to a world record performance by South Africa’s Wayde van Niekerk in the men’s 400, but the Jamaican superstar was clearly the main event.

The sprinters emerged from the tunnel one at a time. Gatlin, with a pair of doping offenses marring the early stages of his career, received a mixed reaction with plenty of boos. But when Bolt’s name was called, the stadium shook. He strutted out like a heavyweight champion before a prize fight. Bolt stretched his arms to the side, not unlike the statue of Christ the Redeemer that watches over this city.

They stood on their feet and chanted “Bolt!” But when he finally settled into the starting blocks, 60,000 people fell silent. The starter’s gun fired, and Bolt’s 6-foot-5-inch frame uncoiled and rocketed ahead. The muted crowd — partisan only in the sense everyone in attendance hoped to bear witness to something great — erupted into a roar.

Here are 10 members of the U.S. track and field team you should know as they compete in the Rio Olympic Stadium. (Lee Powell/The Washington Post)

For Bolt to cover 100 meters, he usually needs about 41 strides. Like most races, this one was decided well before the 41st. Gatlin came out hot, bounding in front of the field. By the time the American became upright and lifted his head, Bolt already was gaining on him.

“He always gets a good start,” Bolt said later. “I just tell myself to take my time and chip away at the lead.”

Running in Lane 6, Bolt moved ahead. His long strides cover so much ground, and it was quickly clear that no one would be catching the Jamaican star. It looked effortless, if only because no one else can possibly mimic him.

“Bolt is Bolt,” said American sprinter LaShawn Merritt, who will take aim at Bolt’s 200-meter crown here. “There’s not a lot of dissecting what he does.”

As Bolt approached the finish line, he cast his eyes on the video scoreboard high above, where even he had a chance to watch history unfold. Easing off the gas, he tapped his chest with his right hand and raised his index finger into the air.

“This is what I came here for,” he explained later, “to prove to the world that I’m the best.” He paused for a beat. “Again.”

Like his previous wins, it was difficult to tell who was having more fun, the fans who had just witnessed history or the runner who had just made it. His victory lap was a one-man party. He posed for cameras, snapped selfies, accepted gifts, even carrying a giant stuffed animal off the track with him.

In another era, statues might be erected of Gatlin. Instead, he had unwittingly carved out eternal bridesmaid status in the sport’s history books long before Sunday’s race began. At the 2012 Olympics, Gatlin lost to Bolt by 0.14 seconds. At the 2013 world championships, he lost by 0.08. And at least year’s world championships, he finished just 0.01 seconds behind.

“When it comes down to it, I guess I’ve given him his closest races in all of his career,” Gatlin said. “To be able to say that at the age I am now, it’s an honor.”

He won gold at the 2004 Olympics but had to settle for silver here, four years after taking bronze. He will have two more shots to unseat Bolt at these Rio Games before both runners prepare for retirement.

“I’m a competitor. He’s a competitor. He has pushed me to be the athlete I am today,” Gatlin said. “I hope he can say the same about me.”

At 34, Gatlin somehow has been posting some of the best times of his life, aging and progressing unlike just about every other elite sprinter who had come before him. Even Bolt, as consistent and dominant as he has been, seemed to plateau to his mid-20s. His world records came seven years ago, and though he was with very rare exception always the first across the finish line, his marks always seemed safe — for now, at least, maybe forever.

Bolt now will take aim at winning his third straight Olympic 200 this week, and then he will try to help the Jamaicans win their third straight 4x100 relay. He made clear to anyone listening late Sunday night that he didn’t come to Rio de Janeiro to win just a single gold medal.

“It’s a good start,” Bolt said.