VALENCIA, Spain - Title favourite Dayron Robles suffered a shock exit in the first round of the 60 metres hurdles at the indoor world championships on Saturday after being left in the blocks in his heat.

The 21-year-old Cuban appeared to think there had been a false start and jogged out of the blocks only to see the rest of the field striding away from him.

Another title contender Liu Xiang from China clocked 7.73 seconds to reach the next round.

China's Liu Xiang competes in the heats of the men's 60m hurdles at the 12th IAAF World Indoor Athletics Championship in Valencia March 8, 2008.

Robles, the second fastest 60-metre hurdler in history who has threatened Colin Jackson's 14-year-old world record of 7.3 seconds, tried to make up the lost ground but ended up crossing the line last in 8.53 seconds.

He threw himself on to the track in frustration and sat with his head in his hands, bemoaning his misfortune.

"It can't be...It just can't be," he said as he left the stadium.

The 21-year-old has produced nine of the year's 11 fastest times. He won silver at the last world indoors championships in Moscow.