Cambodia's 800-metre runner Kieng Samorn failed in his bid to claim a personal best at the London Games yesterday.

In front of a full house at Olympic Stadium, the Ratanakkiri native kept the pace during the first lap but dropped off significantly in the last to finish way back from the pack at 1:55:26, more than three seconds off his target.

World record holder David Rudisha of Kenya won the heat in 1:45:90.

To contact the reporter on this story: Dan Riley at [email protected] reporting from London