American hurdler Aries Merritt has tipped China's Liu Xiang for the gold medal in the 110m hurdles, despite himself running the fastest time this year.

Merritt has run 12.93s on three occasions in the build-up to the London Games but he says that Xiang's experience of the Olympics makes him the favourite for gold.

"This is his third Olympics and this is my first, so he has way more experience than me," Merritt said.

"I have experience when it comes to the world stage, like world championships, but on the Olympic setting, it is a different stage and he has the experience and has a championship."

Xiang is one of only two other competitors to run under the 13s mark this year.