Some saw no reason to wait to see what Bolt does the rest of the way at these Olympics.
"There's no doubt he's the greatest sprinter of all time now," said seventh-place finisher Richard Thompson of Trinidad and Tobago, who was 0.35 seconds back on Sunday.
Thompson was the silver medalist in Beijing, despite trailing Bolt by a hard-to-believe 0.20.
The margin Sunday was 0.12, and Bolt pushed all the way, making up for his usual slow beginning.
After he'd closed out his mugging for the cameras, even pantomiming spinning a record like a DJ, Bolt crouched into the blocks. Right before the starting gun, a plastic bottle was tossed from the stands and it landed on the track behind Blake's lane. But neither Bolt nor Blake noticed.
"When they say, 'On your marks,' that's when the focus starts," Bolt said.
He took a while, as usual, to get up to top speed, but once he found his extra gear, no one else stood a chance, even though the men surrounding Bolt were an accomplished bunch. Once he found himself even with the leaders with about 50 meters left, Bolt did what he does best.
Cheeks puffing, arms pumping right along with each of those lengthy strides — Bolt is taller and leaner than the typical 100-meter champs of the past — he reeled in everyone else, even leaning at the finish for good measure.
"I stopped worrying about the start," Bolt said. "The end is what's important."
Oh, and how he enjoyed what came next.
Bolt, who turns 26 this month, delivered the sort of scene he made so commonplace in Beijing: a look-at-me! series of photo ops, including dance moves fit for a nightclub and what he calls his "To the World" pose, when he leans back and points to the sky.
He hugged Blake, the guy Bolt nicknamed "The Beast" because of his intensity in practices.
Later, Blake tweeted: "Big up (at)UsainBolt! You deserved that one. Big up Jamaica!"
Gatlin didn't begrudge Bolt's enthusiasm.
"He's the Michael Phelps of our sport," Gatlin said, referring to the U.S. swimmer who has won a record 22 Olympic medals, 18 gold. "What can you say? He's a showman. Is it arrogance? Confidence? It's a good show."
Bolt is not the most serious fellow, and he isn't too proud to admit he never has put much emphasis on fitness. In 2008, he explained that his success was fueled by chicken nuggets from a fast-food restaurant in the Olympic village. This time around, he noted that he noshed Sunday on a sandwich wrap from the same chain.
"It was chicken with vegetables, so it was healthy," Bolt said with perfect deadpan delivery. "Don't judge me."
The only judgments now are going to be about where Bolt stands in the pantheon of sprinters and Olympians.
Even LeBron James, Kobe Bryant, Kevin Durant and other members of the U.S. men's basketball team wanted to get a glimpse of Bolt, arriving right as the 100 semifinals were getting started Sunday.
James even pulled out a phone to record video of Bolt in action.
"The whole world is going to watch this tonight," James said. "This is the biggest event of them all, right here."
There were other events on Sunday's schedule, and Sanya Richards-Ross won the only U.S. gold at the track so far. She erased the bad memory of her bronze-medal finish in Beijing by accelerating down the stretch to win the 400 meters in 49.55 seconds.
Other winners were Ezekiel Kemboi of Kenya in the men's 3,000-meter steeplechase, Krisztian Pars of Hungary in the men's hammer throw, Olga Rypakova of Kazakhstan in the women's triple jump, and Tiki Gelana of Ethiopia in the women's marathon. Oscar Pistorius, the amputee "Blade Runner" from South Africa, finished last in his 400-meter semifinal but will get another chance in next week's 4x400-meter relay.
Bolt's victory in the 100 four years ago began a stretch of dominance by Jamaica, an island nation of 3 million people — about 1 percent as many as the U.S. — that now owns seven of the last eight Olympic men's and women's sprinting golds, including relays.
About 1½ hours before Bolt's latest victory, Shelly-Ann Fraser-Pryce stepped to the top of the medal stand in the stadium and received the gold she collected for Jamaica in the women's 100 on Saturday night. Like Bolt, she's a repeat champion.