LONDON - China's 110m hurdles star Liu Xiang had surgery on his badly ruptured Achilles tendon Wednesday as his arch-rival Dayron Robles also limped out of the London Olympics. As China cranked up its dominance of table tennis with another clean sweep, Liu was being treated by a specialist London surgeon -- who reportedly also operated on football star David Beckham. The Chinese delegation said Liu was putting a brave face on the injury which cruelly cut short his campaign for the second Games running, and has possibly ended his career. "He's in pain but he's very brave and optimistic," spokesman Zhang Haifeng told AFP. "It's really a sad thing but his spirit inspires young people very much." No update was available late on Wednesday, but Zhang said the 2004 champion would recover in the athletes village before returning to China. And in a fateful twist, Robles went down with a similar injury in Wednesday's final. The Cuban world record-holder hit a hurdle and pulled up clutching a hamstring, as Aries Merritt took gold ahead of American team-mate Jason Richardson and Jamaica's Hansle Parchment. The final comes a year after the world championships in Daegu, South Korea, when Robles was disqualified for reaching into the next lane and pulling Liu's arm as he powered ahead.