Usain Bolt won a third successive Olympic 200m gold to keep alive his hopes of an unprecedented "triple triple" in Rio.
Thursday's victory was Bolt's 13th individual world or Olympic sprint title from a possible 14 since he took athletics by storm at the 2008 Beijing Olympics.
The 29-year-old Jamaican timed in at 19.78 seconds for gold.
Canadian Andre de Grasse took silver with 20.02 seconds and France's Christophe Lemaitre won bronze with 20.12 seconds.
Huge cheers greeted Bolt as the Guns N'Roses' ''Welcome to the Jungle'' was blasted out. He was wearing black lycra shorts and a singlet in the green, gold and black colours of Jamaica.
The sell-out Olympic Stadium crowd, which has been criticised for its hateful banter of some athletes, were very excited in their welcome of the Jamaican star.
He does it again! Usain Bolt completes the triple-double as he wins 100m & 200m for 3rd straight Olympics. pic.twitter.com/QMZXpNppr4
— SportsCenter (@SportsCenter) August 19, 2016
The win means that Bolt can complete a third straight sweep of the sprint medals -- 100m, 200m and relay -- on Friday in the 4x100m contest when Jamaica start as favourites. The so-called 'triple triple' would see him leave the Olympic stage as an incontestable great.
Bolt, in his favoured lane six, had Lashawn Merritt, the American 400m specialist and sole US medal hope after Justin Gatlin failed to make the eight-man final, just inside him in Thursday's final.
Immediately out of the blocks, the Jamaican was quickly up on Lemaitre, racing in seven.
With the temperature around 27 degrees Celsius (84F) and the track gleaming after a light rain shower, Bolt delivered electrifying control around the bend, hitting the back stretch in full tilt.
As the crowd cheered, Bolt responded by moving into his famous "drive phase", with his head coming slowly up as part of the process that unleashes the full power from his long legs.
Eyes glued on the stadium's big screen at the end of the 100m track, Bolt blasted through the line with a glance leftwards at the giant stopwatch, hitting his chest and saying "number one".
"No, I can't grasp what I've achieved, definitely not," said Bolt.
"You work so hard for years and then you just hope it pays off. It is a brilliant feeling."
But Bolt looked disappointed with his time as he ripped the numbers off his shorts and threw them to the ground.
Bolt admitted that he hadn't felt too good down the back stretch, finishing up at what was his slowest 200m of all his individual victories.
"I wasn't happy with the time," he said. "My body just wouldn't respond in the straight.
"I'm getting older and my body is ageing. Personally I think this is my last 200 but my coach may beg to differ."
Feelings of disappointment were quickly forgotten on the track as Guns N'Roses was switched for Bob Marley's "One Love". Bolt, covered in Brazilian and Jamaican flags, did a lap of honour to chants of "Usain Bolt, Usain Bolt!" after another amazing victory and eighth Olympic gold.