But there were only roars and camera flashes after the starting gun sounded, and though Bolt and Gatlin quickly made up the stagger on the sprinters in adjacent lanes, Bolt — as usual — had the edge coming out of the curve. He crossed the finish line in 19.55 seconds, with Gatlin in second in 19.74.

Bolt had beaten Gatlin by just one-hundredth of a second to win the 100, but the 200 was a much less suspenseful affair as Gatlin was unable to approach his top time earlier this season of 19.57.

“He came through when it was time to come through,” said Gatlin, who was also second behind Bolt in the 100 at the 2013 world championships in Moscow.

Anaso Jobodwana of South Africa took the bronze medal on Thursday, in 19.87 seconds.

Bolt had raced little in the last two seasons because of back problems and other injuries, but as he had done in the past, he managed to peak at the right meet — after making a trip to Germany to visit his longtime doctor, Hans-Wilhelm Müller-Wohlfahrt.

“He just fixed my injury,” Bolt said. “I had problems with my joints, and he just helped me to sort that out pretty much.”

Winning the 100 gave Bolt a mental boost as well.

“Winning the 100 meters always gives you confidence, without a doubt,” Bolt said. “But as I told you guys coming into the world championships, the only thing I was really worried about was the fact that I didn’t get to race a lot through the season. But the rounds really helped me, and the more I ran, the better I felt.