Usain Bolt sealed an unprecedented 'triple-triple' on Friday, leading Jamaica to victory in the 4x100m relay.
What happened?
Bolt bounded over the line in 37.27sec to trigger an eruption of adulation in the Olympic Stadium.
Japan's quartet took a surprise silver in 37.60sec while Canada took bronze after the United States, who crossed in third, were later disqualified.
Why it matters for Usain Bolt
The victory saw Bolt complete a third consecutive clean sweep of the 100m, 200m and 4x100m titles following his six gold medals in the 2008 and 2012 Games.
His ninth gold medal drew him level with Paavo Nurmi, the Finn who dominated distance running in the early 20th century, and American sprinter and long jumper Carl Lewis as the most successful Olympic track and field athletes.
What comes next?
Bolt will now set off a year-long victory tour that will culminate with the World Championships in London next August.
The Jamaican is preparing to exit with athletics fighting to restore credibility after a year dominated by doping and corruption scandals.
International Association of Athletics Federations president Sebastian Coe is adamant however that athletics will endure, despite the loss of its most charismatic leading man.
In an interview with AFP on Friday, Coe said Bolt had transcended his sport in a way that was comparable to boxing icon Muhammad Ali.
Bolt told reporters: 'I'm going to stay up late and have fun. I never knew this would happen when I started out.'
And he added: 'There you go, I am the greatest. I am just relieved. It's happened. I am just happy, proud of myself.'
Bolt will retire in 2017, marking the end of an incredible Olympic career that redefined athletics.
He lingered on the track after his lap of honour, kneeling down to kiss the finish line as chants of 'Usain Bolt, Usain Bolt' echoed from the stands.
Coe argued that just as a new generation of boxers emerged after Ali's retirement, so track and field would unearth new personalities after Bolt.
Bolt's legacy will be remembered for years to come, and his impact on the sport will be felt long after his retirement.
The Olympic Stadium erupted in cheers as Bolt celebrated his historic win, capping off an unforgettable career.