Lisa Dobriskey's hopes of completing a fairytale return with an Olympic medal were ended as she never got into contention in the 1500 metres.
The Ashford athlete has battled back from potentially life-threatening blood clots on her lungs, but, after looking so impressive in the rounds, she could only come home 10th in a slow race in 4:13.02.
She said: "I'm really disappointed actually. I have to be with it and I just wasn't close enough when it came to the crunch. I'm very dejected at the moment."
Dobriskey told the BBC: "I found myself in the wrong place. You have to be right on it when they go and I was too far back. I knew the other girls were very strong and it would have been very hard to have got a medal."
While Laura Weightman, in her first major championship, was 11th in 4:15.60.
She said: "I'm really pleased with that, it was my first major championship and to make the final and come 11th, I can't be too disheartened."