[gallery size="medium" td_select_gallery_slide="slide" td_gallery_title_input="Bolt signs off with triple-triple" ids="78678,78677,78676"] 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 4x100m relay crown in Rio Friday. Two days shy of his 30th birthday, Bolt anchored his country to victory in 37.27 seconds so adding the relay crown to the 100 and 200 meters titles he has owned since exploding onto the Olympic stage in Beijing in 2008. He will depart that stage never having tasted defeat in a final, his nine gold medals a joint record in athletics with Finnish distance runner Paavo Nurmi and American sprinter and long jumper Carl Lewis. In the eight years since Beijing, the 11-time world champion has become one of the best known sportsmen on the planet and with the ‘triple-triple' has a legitimate claim to the title of greatest Olympic track and field athlete ever. There has never been any doubt in the Jamaican's own mind. "There you go, I am the greatest. I've worked hard every Olympics to win three gold medals... so I'm just happy that I've accomplished so much," Bolt told reporters. "It's a relief but I'm also sad that I have to leave. This is my last one... It's just so many special feelings I'm feeling." There is no doubt that Bolt has transformed his sport, if only by almost single-handedly displacing the US as the superpower of men's sprinting. It was only almost single-handedly, though, as his three Olympic relay titles, two in world record times, always required the input of his fellow Jamaican speedsters. Again on Friday, former world record holder Asafa Powell, Bolt's training partner Yohan Blake and Nickel Ashmeade gave the double sprint world record holder the lead at the final exchange, albeit an extremely slim one. That was always going to be enough for Bolt in his final Olympic race, however, and he powered down the straight to finish five meters clear of Japan's Aska Cambridge. Ryoto Yamagata had run 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 tumbled over but the United States still thought they were settling for bronze in 37.62. Since 1995, though, the Americans had failed to get the baton around or been disqualified eight times in sprint relays at the Olympics or world championships and calamity struck for a ninth time Friday. The handover between lead-off runner Mike Rodgers and Justin Gatlin was adjudged to have started before the exchange zone and the Americans were disqualified as they were on their lap of honor. Canada was elevated to bronze after its run of 37.64, a national record which gave Andre de Grasse his third medal of the Games after a bronze in the 100m and silver in the 200m. American Tyson Gay was the last man to beat Bolt in a major championship final — in the 200m at the 2007 worlds in Osaka — and, like many of the other sprinters in the final, 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." Meanwhile, Allyson Felix hit her own landmark with a fifth gold as the US women won their 4x100m relay, a day after winning a reprieve into the final. It brilliantly beat Jamaica to complete a remarkable comeback from disqualification. Felix, long jump gold medalist Tianna Bartoletta, English Gardner and Tori Bowie combined to clock the second fastest 4x100m relay ever run, in 41.01 seconds. Felix is the first women athlete to reach five golds. Greece's Ekaterini Stefanidi won the women's pole vault after virus-stricken defending champion Jenn Suhr crashed out. Stefanidi cleared 4.85 meters to beat American Sandi Morris, who took silver. New Zealand's Eliza McCartney, 19, cleared 4.80m to tie her national record and take bronze. Kenyan former world champion Vivian Cheruiyot reeled in 10,000m champion Almaz Ayana of Ethiopia to win the women's 5,000m title. Cheruiyot, 32, had been the nearly woman in her last three Olympic finals, winning two silver medals and one bronze, but she ran a superb tactical race to win in 14.26:17. Her compatriot Hellen Onsando Obiri clocked a personal best of 14:29.77 to take silver. Ayana had to settle for bronze. China's Liu Hong pipped Mexico's Maria Gonzalez by just two seconds to win the 20km walk. Liu timed 1hr 28min 35sec with Gonzalez right behind her, while another Chinese walker, Lu Xiuzhi, took bronze in 1:28:42. Dilshod Nazarov handed Tajikistan its first ever Olympic gold medal when he won the men's hammer throw. Nazarov heaved a best of 78.68 metres to finish ahead of Belarus' convicted doping cheat Ivan Tsikhan (77.79m). Poland's Wojciech Nowicki claimed bronze with a best of 77.73m. In other events, Chloe Esposito won the women's modern pentathlon gold, giving Australia its first medal in the five-discipline event. Esposito posted an Olympic record of 1,372 points. Elodie Clouvel of France won silver with 1,356 points and bronze went to Poland's Oktawia Nowacka with 1,349. Great Britain's Nick Skelton riding Big Star won the individual showjumping gold. Skelton, 58, triumphed in a six-way jump-off with a clear round in 42.82sec. Sweden's Peder Fredricson aboard All In took silver with the only other clear round of the jump-off, while Canada's Eric Lamaze and Fine Lady 5 earned bronze. South Korea's Park In-bee goes into the last day of the women's golf — returning to the Olympics after 112 years — with a two stroke lead over New Zealand's world No. 1 Lydia Ko. The 19-year-old Ko hit her first ever hole-in
