The world's fastest man is marching on.

Jamaican sprinter Usain Bolt returned to competition at the 2012 London Games Tuesday, fresh off his victory in Sunday's 100-meter finals. Bolt advanced to the semifinals of the men's 200 meter sprint, along with teammate Yohan Blake, the 100-meter silver medalist.

Americans Wallace Spearmon, Maurice Mitchell and Isaiah Young also advanced. The 200-meter final is set for Thursday night.

Tuesday also brought more disappointment for Chinese hurdler Liu Xiang. The 2004 gold medalist in the 110-meter hurdles hit the first hurdle in his opening round race, crashed to the track and had to be carried off. Back in 2008, at the Beijing Games, Liu was forced to withdraw due to a foot injury to the disappointment of his countrymen.

Later Tuesday, Kenya's Asbel Kiprop goes for gold in the men's 1,500-meter final. Kiprop is the reigning Olympic champion but is expected to face a stiff challenge from Algeria's Taoufik Makhloufi.

In the women's competition, Australian Sally Pearson is the favorite in Tuesday's 100-meters hurdles gold against Americans Dawn Harper, the defending Olympic champion, and Lolo Jones.

Host country Britain added to its medal tally with gold in the men's triathalon and a silver in sailing.

The Brits are also hoping for more gold on the cycling track as Chris Hoy races in the men's keirin , while Victoria Pendleton battles Germany's Kristina Vogel in the semi-finals in the women's individual sprint and a chance for a possible matchup against Australia's Anna Meares, who will face China's Guo Shauang in the semi-finals.

China leads the overall medal count for the 2012 London Olympics with 65, including 32 gold. A close second is the United States with 63 medals including 29 gold. Britain is in third , with 43 including 19 gold.