Usain Bolt farewelled the Olympics with a ninth gold medal

Usain Bolt farewelled the Olympics with a ninth gold medal after anchoring Jamaica to triumph in the men's 4x100 metres relay final in Rio.

Bolt was backing up on Friday (Rio time) a night after completing his third Olympic sprint double and he added another relay gold to those he had won with Jamaica in 2008 (Beijing) and 2012 (London).

He took the baton on the final leg from team-mate Nickel Ashmeade slightly down on Japan anchor Aska Cambridge but he unleashed a powerful display down the front straight to stop the clock in 37.27 seconds.

"I am just relieved, it's happened," Bolt said.

"I am just happy, proud of myself. It's come true. The pressure is real. I look at it as an accomplishment."

Bolt had a simple message when asked how he would celebrate now his Olympic career is over.

"I'll stay up late tonight," said Bolt, who turns 30 on Sunday.

Asafa Powell, who was part of the Beijing victory, and Yohan Blake, a member of winning London quartet, had opened the relay for Jamaica.

Japan did brilliantly to win silver in 37.60 and Canada - with 100m bronze medallist Andre De Grasse running the final leg - was third in 37.64.

United States was disqualified, continuing the poor showing in an event it once dominated.

It last won gold in 2000 at the Sydney Games.