( CNN ) -- Defending champion Usain Bolt was sensationally disqualified for a false start in the men 's 100-meter final at the world athletics championships in Daegu , South Korea , allowing fellow-Jamaican Yohan Blake to collect an unexpected gold medal . Bolt has dominated men 's sprinting since winning 100-meter and 200-meter gold at the Beijing Olympics in 2008 , achieving the same feat at the world championships in Berlin the following year -- smashing the world record in the process . And although he had not entered this year 's worlds in top form , the absence through injury of rivals Asafa Powell and Tyson Gay meant he was the hot favorite to retain the first part of the sprint double . However , the 25-year-old fell foul of the current false start rules , which state that any athlete who jumps the gun is immediately disqualified . Bolt knew immediately he had started too early and was helped off the track , head in hands , with a packed stadium watching on in disbelief . Once the race did eventually get under way , a muted atmosphere ensued as Blake -- a training partner of Bolt -- powered home to win in 9.92 seconds . American Walter Dix , the Olympic bronze medallist , took silver with a time of 10.08 seconds with veteran 2003 world champion Kim Collins of St. Kitts and Nevis claiming a superb bronze medal . `` I ca n't find words to explain it . Usain Bolt has been there for me . I feel like I want to cry , '' Blake told reporters . `` I felt I would win the race for Bolt . '' Despite Bolt 's shock exit , it proved a good day for defending world champions , with three athletes retaining the titles they won two years ago in Berlin . American Brittney Reese retained her women 's long jump title , and compatriot Trey Hardee won a second consecutive decathlon gold medal . Meanwhile , Russian Valeriy Borchin was another to retain his title , coming home first in the men 's 20-kilometer walk . Li Yanfeng of China secured gold in the women 's discus , but there was heartache for Ethiopian distance legend Kenenisa Bekele , whose attempts at a fifth consecutive men 's 10,000-meter world title came to an end after he was forced to pull out of the final with groin and hip injuries . However , the gold medal still went to Ethiopia with Ibrahim Jeilan outsprinting Briton Mo Farah in a devastating burst to the line . Meanwhile , Oscar Pistorius made history by becoming the first amputee athlete to compete in world championships history . The South African , who runs with carbon fiber prosthetic running blades , came third in his men 's 400-meter heat to qualify for Monday 's semifinal , with the final on Tuesday .
Defending champion Usain Bolt disqualified from the world 100m final . The Jamaican sprinter was stripped of his gold medal after testing positive for a banned substance at an athletics meet in July. Compatriot Yohan Blake wins gold with silver going to American Walter Dix . Ethiopian legend Kenenisa Bekele misses men 's 10,000m final through injury .