As the cameras flashed and the night sky lit up, Usain Bolt sprinted by his competitors. He kept running, screeching past the history books, lapping the sport’s icons and leaving the bar-stool debates in his dust. It really didn’t matter what numbers appeared on the stopwatch at the conclusion of one of the memorable races in Olympic history, and it didn’t matter that 80,000 witnesses spilled into the London streets in stunned amazement.

The Unbelievable Usain Bolt Show at these Olympics was never intended to be a one-night engagement.

“This is where I want to become a legend,” the Jamaican promised Sunday night, “and that was one step.”

Bolt, 25, finally left Olympic Stadium after midnight, and he had no plans to go out on the town, no time to celebrate his Olympic record in the men’s 100 meters. Pushing aside all those doubts about his health and his work ethic, Bolt had just posted the second-fastest 100-meter time the world had ever seen. Yet he insists his legacy is tied to defending both his Olympic titles — in the 100- and 200-meter races — an improbable feat that perhaps no one but Bolt would even imagine.

He’s halfway there. His finish in 9.63 secondsSunday blew away a talented field. Not only did the victory make him only the second sprinter to win the 100 meters in consecutive Olympics, but it means Bolt’s racing résuménow boasts the three fastest performances in history. With the world tuned in and Prince William and Prince Harry in attendance, Bolt left no doubt who is king.

“A lot of people doubted me,” he said. “There was a lot of people saying I wasn’t going to win. There was a lot of talk. For me, it was an even greater feeling to come out, defend my title and show the world I’m still No. 1. I’m still the best.”

He left no doubts about that Sunday. The others had the misfortune of being born in the wrong era. Jamaican Yohan Blake, 22, took silver with a time of 9.75 seconds, and American Justin Gatlin, who recently returned to the sport after a four-year drug suspension, won bronze in 9.79, edging countryman Tyson Gay by 0.01 of a second. Those times would’ve been good enough for gold in any Summer Games that didn’t include Bolt.

The Americans never really stood a chance. Nobody did. After some pre-race showmanship for the crowd and the cameras, Bolt burst out of the blocks quickly and had an edge on the field by the race’s midpoint. Even the other sprinters felt his dominance.

“You can’t miss him,” Gatlin said. “When his legs lift, you feel it, you see it.”

It was different this time for Bolt. While winning gold in Beijing introduced him to much of the world, repeating in London tasted sweeter, he said. The critics and uncertainty fueled him, as both his mind and body were in question. Bolt pulled out of his most recent race last month citing a hamstring injury and was disqualified for a false start last year at the world championships. It was clear that repeating as an Olympic champion would be no simple task.

“When you get to the top, you there, you know it’s good and you’re working and you’re enjoying it,” Bolt said. “Sometimes you lose sight of what’s going on around you. Because, yeah, you know what it takes to get there, but sometimes you lose sight because everybody thinks you’re doing great and you’re doing well.”

The turning point for Bolt apparently came in June at the Jamaican trials, where Blake beat him in both the 100 and the 200. If Bolt couldn’t win his own country’s title, how could he win the world’s?

“Yohan gave me a wake-up call,” Bolt said. “He knocked on my door and said, ‘Usain, this is an Olympic year. Wake up.’ ”

With Bolt both healthy and hungry, the stage was set for a historic race.

Seven of the eight participants in the race broke the 10-second mark. At the 2008 Games, just six sprinters in the final did. At the 2004 Games — where Gatlin took gold — the number was five.

Gatlin ran six-tenths of a second faster Sunday than in his gold medal performance in Athens and barely won bronze over Gay.

“I’m just so glad to be a part of history,” Gatlin said of Sunday’s race.

And everyone in the stadium seemed happy to witness it.

For Bolt, however, the story of the London Games isn’t over. The 200-meter final, his signature race, is Thursday, and only when he defends that title, he says, will he feel accomplished here.

“People can talk a lot,” he said. “You can say anything you want. Showing up and doing what you got to do is a different thing. To me, it was all business.”