Liu Xiang's bid to banish h*s Beijing Olympics nightmare ended in disaster Tuesday as the Chinese athletics icon crashed out of the 110m hurdles when he smashed into the first barrier.

The 29-year-old former world record holder — winner of the 2004 Olympic crown -- had been left distraught four years ago after he was forced to withdraw just moments before his opening race in front of his home fans.

But his return to the Olympic arena on Tuesday lasted only a split second when he ploughed into the first hurdle with his left leading leg and crashed heavily to the floor.

Liu — who has been troubled by back and foot problems in the past month -- eventually got up and hopped down the track to be embraced by his fellow competitors.

He was helped off the track by Britain's Andy Turner and Spain's Jackson Quinonez and then taken to the medical centre in a wheelchair.

Fellow competitor Balazs Baji of Hungary had waited for Liu at the finish line, taking the Chinese star's hand in his and raising the former champion's arm to the stunned crowd.

"When I was a kid I saw him break-

ing a world record, winning the Olympic Games in Athens, so he's a great idol for me. I'm sorry that he fell. It must be really bad for him," he said.

American Aries Merritt, the leading hurdler this season, said he felt sorry for Liu but didn't see anything untoward about him physically al the warm-up.

"It was just terrible. For that to happen to one of the best hurdlers of all time is just a tragedy and I hope he's OK," said Merritt, whose achievement in running the fastest ever Olympic heal of 13.07sec was overshadowed by Liu's distress.

"He looked fine before the race, like nothing was wrong with him. He warmed up great. He always has a good warm-up and he was happy and so I don't think anything was wrong with him going into the race.

"I just think he made a small mistake, like he ran up on the hurdles a little bit loo quickly and he wasn't prepared to take the hurdle at such velocity. He hit it and if you hit a hurdle in the fashion that he hit it there's no way to recover from something like that."

Turner had been racing in Liu's heat and waited for him to hobble down the track before helping him into the wheelchair.

"I have Achilles problems as well," said the 31 -year-old, who won a bronze

medal behind Liu at the world championships in Daegu last year.

" I know what it feels like to be in pain like that. I regard him as probably the best hurdler in history. I have so much respect for him so it was horrible seeing him limp off like that.

"When you medal with people you have a kind of connection and after last year in Daegu we always say hello, try and have a chat in what little English he speaks but he's a nice guy and I wouldn't wish that on my worst enemy."

Liu's dream of winning gold in front of his home crowd at the Beijing Olympics in 2008 ended in one of the great Olympic anti-climaxes as he turned up for his heal but failed to clear a hurdle, clearly hindered by his Achilles tendon injury.

His career has been hampered by injuries ever since he took gold and equalled the then world record held by Colin Jackson of 12.91 sec at Athens in 2004.

He was to go on and better it with a lime of 12.88sec and also win a world title in 2007 but a succession of injuries have taken their toll.

However, he showed the old spark in the world championships last year and was flying when he was twice hindered by 2008 Olympic champion Dayron Robles and ended up third only to be promoted to second when the Cuban was disqualified from top spot.