Unbeatable Bolt signs off with triple-triple
Bolt ran the anchor leg as he won in 37.27 seconds to add the relay gold to the 100m and 200m titles.
RIO DE JANEIRO - Usain Bolt drew down the curtain on his brilliant Olympic career by securing a sweep of the sprint titles for a third successive Games when Jamaica successfully defended the 4x100 metres relay crown on Friday.
Two days before his 30th birthday, Bolt ran the anchor leg as the Jamaicans won in 37.27 seconds to add the relay gold to the 100 metres and 200 metres titles he had won for a third straight Olympics.
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.
"There you go, I am the greatest," Bolt told reporters. "I am just relieved. It's happened. I am just happy, proud of myself. It's come true. The pressure is real. I look at it as an accomplishment."
Ryoto Yamagata ran a blistering opening leg for Japan, who won a stunning silver for their first Olympic medal in the sprint relay in 37.60, improving the Asian record they set in qualifying.
Trayvon Bromell's dip for the line was so aggressive that he stumbled over and the United States thought they were settling for bronze in 37.62.
The situation went from bad to worse, though, when they were disqualified along with Trinidad and Tobago. TV pictures showed Bromell stepping into Bolt's lane in the run to the line.
"I'm hoping we can an appeal of some kind, but we're seeing that the result is a disqualification, so I'm hoping we can appeal that," said former world record holder Tyson Gay.
Canada were elevated to bronze after their run of 37.64, a national record which gave Andre de Grasse his third medal of the Games after his bronze in the 100m and silver in the 200m.
It was the only medal that Bolt was going for that required the input of anyone else but Asafa Powell, Yohan Blake and Nickel Ashmeade gave the double sprint world record holder the narrowest of leads at the final exchange.
That was always going to be enough, though, and Bolt powered down the straight to finish five metres clear of Japan's Aska Cambridge.
Gay was the last man to beat Bolt in a major championship final, in the 200 metres at the 2007 worlds in Osaka - and despite his disappointment at the disqualification he had nothing but praise for the Jamaican.
"He's a great sprinter," Gay said. "That's just self-explanatory. Words can't describe that type of a guy and what he's done for the sport. Everybody just appreciates what he's done."