Even as age has slowly caught up with him, Usain Bolt remains timeless.

The most charismatic athlete in the Olympics, the greatest sprinter in history, a colossal figure that transcends all sports, engineered the picture-perfect send-off on Friday.

He delivered on his promise of clinching the "triple treble" at the Rio Games by leading Jamaica - he ran the anchor leg of course - to victory in the 4x100m.

It meant Bolt, who celebrates his 30th birthday today, has swept the 100m, 200m and 4x100m relay titles at three consecutive Games.

Together with team-mates Yohan Blake, Asafa Powell and Nickel Ashmeade, the foursome stopped the clock at 37.27sec.

Japan (37.60) were surprise silver medallists. The United States crossed the line in third (37.62) but were disqualified after the race for an illegal baton exchange and fourth-placed Canada (37.64) were promoted to the podium.

Jamaica's winning time was the fourth-fastest time in history. With Bolt in the side, they hold the world record of 36.84 (set at London 2012) as well as the next five fastest times.

Bolt's reign began in Beijing, moved on to London and reached its climax in Rio. It has been a demonstration of unsurpassed dominance fused with longevity.

"There you go. I'm the greatest," said the grinning Jamaican, who returned to the track after most of the lights had been turned off. He threw the javelin a few times for fun and posed with volunteers.

Few would argue with him. His nine-gold haul matches American sprinter and long jumper Carl Lewis and Finland's 1920s long-distance runner Paavo Nurmi for most on athletics' all-time Olympic list. He also has 11 world titles.

There was no secret, noted Bolt, whose unblemished doping record is in sharp contrast to the sport's dark history with drugs.

"Dedication. I wanted it the most. I was never satisfied.

"I hope I've set the bar high enough that no one can do it again...

"Nothing is impossible, I never set limits for myself. I've always wanted to push the barriers and that's what I did."

He has repeatedly stressed that Rio will be his final Olympics and he does not intend to race at Tokyo 2020. Next year's World Championships in London, where he will run the 100m and 4x100m, will be his last major international outing.

A career defined by the stopwatch has perhaps given Bolt an impeccable sense of timing; he is exiting sport's grandest stage at the right moment.

The cracks were beginning to show. He won the 100m in 9.81, a far cry from his world record of 9.58 (set at the 2009 World Championships in Berlin).

He won the 200m in 19.78, which was his slowest time over half a lap in a major final since 2008 and significantly slower than his 19.19 world mark (also in Berlin). Even the 4x100m time was slower than London (36.84) and Beijing (37.10).

Bolt said: "I'm definitely going to miss the crowd and their energy. And the competition. I love competing. I'm going to miss all that. It's been a great career."

It was a poignant farewell for one of sport's global icons.

Bolt kissed the finish line, did a victory lap with his 4x100m team-mates, draped himself in both the Jamaica and Brazil flags as he posed for pictures - baton still in hand - and was greeted by congratulatory hugs from Greece's pole vault champion Ekaterini Stefanidi and Kenya's 5,000m winner Vivian Cheruiyot.

Everyone inside the 60,000-seater Olympic Stadium, which was filled almost to capacity every night he ran in a final, sensed the end of an era.

Some, like Blake, who is seen as Bolt's heir apparent, wanted more. He said: "We wanted to win to make Usain immortal and he is immortal. I've told him he should come back for 2020."

During the week, Bolt had been compared to Pele, Muhammad Ali and Bob Marley. He had tossed around words like "immortal", "legend" and "the greatest" to describe himself.

But one undeniable fact remains. There will never be another Usain Bolt.