Bolt plans to retire after next World Championships in London
Usain Bolt has won the ninth gold medal of his career, a historic end to what he has promised will be his final Olympic Games.
The world's fastest man led the Jamaican team to a spectacular victory in the 4x100m men's relay, storming over the line in 37.27 seconds to an explosion of cheers from the crowd.
The win is the final piece in an unprecedented "triple triple" medal sweep for the sprint superstar, after success in the men's 100m and 200m finals.
He has now won three gold medals in three successive Olympic competitions.
It leaves him level with American sprinter and long jumper Carl Lewis and 20th Century Finnish distance runner Paavo Nurmi on a total of nine Olympic gold medals, a record for a track and field athlete.
Bolt, who turns 30 on Sunday, became the first man in history last week to win a hat-trick of 100m gold medals.
He now also leaves the Olympic stage as just the second man to win the 4x100m three times.
"I'm just happy that I've done what I came here to do," he said after the race, joking there would have been grave consequences for his teammates if they had let him down.
"I told the guys I'd beat them up," he said.
Luckily for Bolt's teammates Asafa Powell, Yohan Blake and Nickel Ashmeade it didn't come to that. They gave Jamaica a narrow lead before handing the baton to the world record holder.
It was all that Bolt needed and he sprinted to the finish several metres clear of his nearest rival.
Japan took a surprise silver, while Canada was promoted to bronze after the United States, which came in third, was disqualified.
Bolt plans to bow out of athletics after competing in the World Championships in London next August.