Great Britain's Chris O'Hare has admitted that he is "really disappointed" to have run "like a donkey" in his 1500m semi-finals.
The 24-year-old was in a strong position towards the front of the pack until the final 200m of the race, where he tired to finish sixth in a time of 3:44.36.
"I felt good at the bell, felt fine until 100m to go but my last 50m was rubbish," O'Hare told BBC Sport. "I am really disappointed, I wanted to do a lot better than that.
"It's horrible to come here and run like a donkey. It is a big year next year and hopefully I can run better than that."
O'Hare's compatriot Charlie Grice qualified for the final after finishing fourth in the second semi-final.