The world gasps as Liu walks away from Men's 110m Hurdles

China's Liu Xiang reacts after getting injured.

In the biggest upset of the Beijing 2008 Olympic Games for host country China, world and Olympic champion Liu Xiang stumbled at the start of his qualifying heat in round one of the Men's 110m Hurdles on Monday morning. He later withdrew entirely from the event.

After Mohammed Issa Al-Thawadi of Qatar in lane three made a false start, Liu slipped off the blocks himself. When the athletes gathered at the start to get set a second time, Liu was conspicuously absent.

"A 110m Hurdles race without Liu is such a pity," Al-Thawadi said after the race. "I really wanted to be just next to Liu's lane because he's such a big champion. It's a great pity I lost an occasion to race with him. I hope he will come back soon."

At a press conference following the event, Liu's coach confirmed that the star's withdrawal was as a result of an injury to his right take-off foot, which has been affecting him for about six years. Liu reported on his own website Sunday that he was suffering from a sore Achilles tendon.

Liu's showdown with Dayron Robles, the Cuban who took away his world record earlier this summer, was one of the most eagerly-anticipated events of the Games.

During his warm-up, Liu grimaced as he attempted to stride over a set of two hurdles. He stepped onto the track with the other runners in his heat and warmed up in his start lane. In one practice run, he fell to his knees and held his leg.

After the false start, he attempted a run several times, but eventually shook his head, removed his race numbers and began to repeatedly kick a wall.

Liu took first place at the world championships in Osaka, Japan, last year with a time of 12.95 seconds, but has yet to break 13 seconds this year or even turn in a top 10 performance.

Robles overtook Liu's world record in April 2008 when he ran 12.87 at the Ostrava Grand Prix in Czech Republic. The Cuban just missed out on a medal at the 2007 World Championships when he finished fourth. So far in 2008, he has run 13.01s at the Shanghai Grand Prix and 13.20s at the Berlin Golden League meet.

Terrence Trammell of the United States was also disappointed after failing to finish his race due to an injury. He was looking to finally win a gold medal after earning four major silver medals in his career.

The 29 year-old took silver at the Sydney 2000 and Athens 2004 Olympic Games. He has twice finished second at the World Championships, in 2003 in Paris, and 2007 in Osaka when he ran 12.99, the first time he went under 13 seconds in a major final.

In the same lane Liu was assigned to run in one heat later, Trammell fell dramatically after hurting his hamstring.

"He's a veteran in hurdles for the United States, and we're going to have to pick it up and make sure we represent the US," said David Payne, after seeing his teammate fail to finish his race.

David Oliver of the United States enters round two as the fastest qualifier, after running a time of 13.30 seconds, putting him ahead of Colombia's Paulo Villar in 13.87s and Ryan Brathwaite of Barbados, who ran 13.38s.

Cuba's Dayron Robles clears a hurdle.

Robles moves on after running a relaxed 13.39s to win the first heat.

Round two will be held tomorrow night, August 19, at the National Stadium.