BEIJING -- Usain Bolt beat Justin Gatlin to win the 100-meter world title in 9.79 seconds at the Bird's Nest, where he shot to fame at the 2008 Beijing Olympics with his victories in world-record times in the 100 and 200.
The only time Bolt has failed to win gold in a sprint at a major championship since the 2008 Games was when he was disqualified for a false start at the 2011 worlds.
Gatlin, who won the 100 at the 2004 Olympics before serving a four-year suspension for doping, had been unbeaten in 2015 and had the season-leading time of 9.74 but placed second in 9.80.
The 33-year-old American took bronze behind Bolt at the 2012 Olympics and silver at the 2013 world championships in Moscow.
The biggest showdown in years materialized despite a shocking stumble from Bolt in the semifinals. Allways the hesitant starter, Bolt stumbled out of the blocks and had to chase hard throughout his heat to qualify in 9.96 seconds.
The confident swagger ahead of the race immediately changed into a disgusted shaking of the head after the early error almost cost him the final.
"I think I hit my foot too hard," Bolt said. "I just stumbled. I really don't know what happened."
The Jamaican great had as many as seven racers to catch before winning the heat. Anxious, he spent the last 10 meters looking to his left to make sure he would make the final.
As much as Bolt's race was chaotic, Gatlin's heat was sheer perfection -- fast out of the blocks, great acceleration and a lightning fast pumping stride before he started coasting. And he still finished in 9.77 seconds, a time Bolt has not come close to this year.
"Easy. Breezy," Gatlin said.
It more than showed the challenge Bolt faces in Sunday's final, like overcoming memories of that stumble.
"I'm not worried about that. I'm worried about being consistent," Bolt said.
At the world championships in Daegu four years ago, Bolt false-started in the final of the 100, the only blot on his record of perfection since winning three gold medals with as many world records at the 2008 Beijing Olympics.
In the third semifinal heat, Tyson Gay qualified in the same time as Bolt, even though he didn't stumble. Asafa Powell also joined them in the final.
Gatlin, the 2004 Olympic gold medalist, is reaching his peak form at 33 after serving a four-year doping suspension midway through his career.
The 100 final takes center stage on a night with three other gold medals at stake.
Three years after the 2012 London Games, and now a mother, Jessica Ennis-Hill remains the heptathlon standout she once was. With three solid performances in the long jump, the javelin and the concluding 800, the Olympic champion -- then known as Jessica Ennis -- won her second world title, six years after her first.
Runner-up Brianne Theisen-Eaton needed to make up about six seconds in the 800 to win and went out fast to pressure Ennis-Hill with an early burst of speed. But Ennis-Hill kept her within striking distance and swept past the Canadian in the finishing straight.
Ennis-Hill won with 6,669 points, 115 points ahead of Theisen-Eaton. Laura Ikauniece-Admidina of Latvia took bronze with 6,516 points.
In the men's hammer throw, Pawel Fajdeck of Poland retained his world championship title by winning with a best mark of 80.88 meters, beating three-time Asian Games champion Dlishod Nazarov of Tajikistan and another Pole, Wojciech Nowicki.
The host nation again fell short of a gold medal when Miguel Angel Lopez of Spain held off a strong challenge from Wang Zhen to win the 20-kilometer walk.
Even though Wang had been undefeated for a year, he entered the Bird's Nest when Lopez was already moving toward the finish line celebrating a gold medal to add to his European title from last year. Benjamin Thorne of Canada was third.
