Jamaica’s Usain Bolt became the first athlete to win three Olympic 100m titles by beating American Justin Gatlin to gold at Rio 2016.
Bolt, 29, ran 9.81 seconds in his final Olympics to replicate his success at Beijing 2008 and London 2012.
Gatlin, twice banned for doping offences, finished 0.08 seconds behind Bolt to take silver.
“I expected to go faster, but I’m happy that I won,” Bolt told BBC Sport. “I’m here to perform. I did what I had to.”
Canada’s Andre de Grasse took bronze in a personal best of 9.91, ahead of Bolt’s Jamaican team-mate Yohan Blake.
There was no British interest in Sunday’s showpiece as James Dasaolu was eliminated in the semi-finals.
Bolt remains on target to leave Rio with a third successive Olympic treble after winning the 100m, 200m and 4x100m relay titles in 2008 and 2012.
The world record holder said in February he would retire from athletics after the 2017 World Championships.
“Somebody said I can become immortal. Two more medals to go and I can sign off immortal,” he said.
Bolt was slower out of the blocks than 34-year-old Gatlin, who was aiming to regain the title he won at Athens 2004.
But he surged through from 60 metres to pass Gatlin and comfortably win his seventh Olympic gold.
Bolt received a hero’s reception as he walked out into Rio’s Olympic Stadium before the race, and the crowd chanted his name after his victory.
“It wasn’t about the time, it was just about winning the gold and going out on top,” said Michael Johnson, four-time Olympic champion and BBC Sport analyst.