China's Liu Xiang clears a hurdle in a Men's 60m hurdles heat during the World Indoor Athletics Championships in Istanbul, Turkey, Saturday, March 10, 2012. (AP Photo/Matt Dunham)

Shanghai – Chinese hurdler Liu Xiang endured injury agony at the Beijing Olympics and bitter injustice at last year's world championships, but now he looks on the verge of redemption in London.

It's been a long road back for the unassuming “Flying Man”, 28, who won 110m hurdles gold at Athens 2004 but was struck down by an Achilles injury in Beijing, a bleak moment in an otherwise glittering Olympics for the hosts.

Liu's withdrawal in severe pain, without even clearing a hurdle in his first heat, caused such profound shock that fans flooded out of the Bird's Nest stadium and a Chinese TV presenter wept as he announced the news.

It was the start of the long spell in the doldrums for Liu, who had claimed China's first ever sprint gold in a world record-equalling 12.91sec in Athens, and lowered the mark to 12.88

two years later in Lausanne.

American surgeons removed calcium deposits from his right Achilles tendon in December 2008, but it was more than a year after Beijing before he returned to the track in his home city of Shanghai.

But Liu remained troubled by the injury and he took another six months off in 2010 before returning to form with Asian Games gold that November, clocking 13.09 in front of a huge crowd in China's Guangzhou.

The breakthrough came in May last year when Liu, with a new starting technique of taking seven strides rather than eight to the first hurdle, glided over the barriers to shock in-form American David Oliver in Shanghai.

It set up a mouth-watering world championships final two months later in Daegu, South Korea, featuring Liu, Oliver and reigning Olympic champion Dayron Robles, the world record-holder from Cuba.

Liu was accelerating smoothly over the last third and looked set to overhaul Robles, leading in the next lane, at the line.

But the Cuban reached across and grabbed Liu's arm once before the last hurdle and once again after, checking his momentum as the Chinese runner finished third.

Robles was later disqualified, handing the title to America's Jason Richardson, while Liu was awarded silver. Although there was outrage in China, Liu took the incident calmly.

Revenge could be on the menu this year. In the current season, Liu has beaten Robles over 60 metres in Birmingham and he came second to Aries Merritt in the world indoor championships in March.

Outdoors, he has enjoyed convincing wins in Kawasaki and Shanghai, where he left Oliver and Richardson trailing. At the Prefontaine Classic, he equalled Robles' world mark of 12.87, aided by wind.

Liu's personal best, the former world record of 12.88, is now six years old, and his last world title came in Osaka 2007.

But in London, he can cap a momentous comeback by claiming a second Olympic gold medal, along with retribution over Robles – and, if the stars align, erase the Cuban's 12.87 from the record books.

“I hope to compete against him. But I want to say that every athlete is strong. He is only one,” shrugged Liu about Robles. “I'm not so bad myself.” – Sapa-AFP