Niall Flannery has claimed that his performance in the semi-finals of the 400m hurdles in Beijing was not as smooth as he produced in his heat.
The Essex athlete, Great Britain's sole representative in the event, tried to save energy for the second half of the race, but was unable to catch Michael Tinsley and Nicholas Bett, who took automatic qualification.
However, Flannery has admitted that he was expecting a better performance than what he delivered.
"Initially, I'm really disappointed. After yesterday I was quite confident of running a 48.50 which would have got me into the final," Flannery told BBC Sport.
"It wasn't as smooth as yesterday and the bit that went wrong yesterday went worse today, which is annoying. Hopefully next year it'll be a different story."
Flannery's time was not quick enough to take a fastest loser's spot in Tuesday's final.
