Ireland's Alistair Cragg had to settle for 14th in the 5000m final on the last day of the World Championships in Daegu after losing contact with the leaders midway through the race.
Cragg, 31, was prominent for the opening six laps but an injection of pace by Saudi Arabia's Hussain Jamaan Alhamdah saw the Irishman drop back.
Mo Farah took gold in 13:23.36 ahead of Bernard Lagat (13:23..64).
Cragg, whose set his personal best of 13:07.10 in 2007, clocked 13:45.33.
South African native Cragg had performed well to make his first global final since the 2008 Olympics in Beijing by qualifying automatically from his heat on Thursday.
A medal was never going to be a realistic prospect for the 2005 European Indoor 3000m champion but Cragg would have hoped to have stayed with the leaders for the majority of the race.
Cragg was untroubled by the slow early pace but the Saudi Arabian's injection of a 60-second lap shortly before the 3000m mark saw the Irishman drop off the leading pack.
The Irish hopeful was 15th of the 16-strong field across the line with only New Zealand's Jake Robertson (14:03.09) behind him.
However, third-place finisher Ethiopia's Imane Merga was later disqualified for stepping onto the infield during the race which saw his compatriot Dejen Gebremeskel promoted to bronze.
Unlike his two previous major finals, the 2008 Olympics and last year's European Championships, Cragg did have the consolation of finishing Sunday's race.
"That was a tough race for me! Sorry to have disappointed those who were rooting for me," Cragg posted on Twitter.