Rio de Janeiro, Aug 15 (IANS): Sprint king Usain Bolt has said he was a step closer to immortality after becoming the first man to win three consecutive Olympic 100-metre gold medals.

The Jamaican finished in 9.81 seconds, beating rival Justin Gatlin of the United States by eight hundredths of a second at the Olympic Stadium here on Sunday. Canada's Andre de Grasse took bronze in 9.91, reports Xinhua.

It was the seventh Olympic gold medal of Bolt's career as he confirmed his status as the greatest sprinter in history.

The result kept intact Bolt's hopes of being the first man to achieve an unprecedented triple-triple: three successive Olympic gold medals in the 100m, 200m and 4x100m relay.

"It was brilliant. I didn't go so fast but I'm so happy I won," Bolt said after winning on Sunday. "I told you guys I was going to do it."

"Somebody said I can become immortal. Two more medals to go and I can sign off. Immortal."

Bolt suffered an injury scare at the Jamaican Olympic trials last month, forcing him to seek treatment in Germany.

He said he never doubted his fitness, nor his ability to beat rival Justin Gatlin, who had held the fastest time of the year in the event before Sunday.

"There will always be doubters. But I'm in better shape than last season," the 29-year-old said.

Bolt enjoyed overwhelming support from the Rio crowd while Gatlin was roundly jeered. The 34-year-old American won the 100m gold medal at the Athens 2004 Games but later served a four-year ban for doping.

"That's the first time I've gone into a stadium and they've started to boo," Bolt said. "It surprised me."

Gatlin was upbeat after the race but hinted he could retire from the sport. 

"We work 365 days a year to be here for nine seconds. At the age of 34, to race these young guys and still make the podium feels so good."