Liu Xiang must run within 12.95 seconds to guarantee the title of the men's 110-meter hurdles at London Olympics, Liu's coach Sun Haiping told TV media yesterday.

"It is difficult for him to take the gold, but I will try to make him in best form," Sun said. "American Aries Merritt will be a tough opponent and Liu must try his best."

Merritt has run in 12.93 three times in 2012. Liu's best time this year was 12.97.

The men's 110m hurdles in London Olympics will be held from August 7-8.