Eilish McColgan blamed injury after she suffered World Championship disappointment in the 10,000m.
The 31-year-old, expected to have an outside shot of a medal having run the second quickest 10,000m this year, finished 10th in the final at Hayward Field on Saturday.
McColgan, looking to emulate mum Liz who won gold in the event in 1991, helped set the pace but dropped to seventh with eight laps remaining and with six left she was struggling to keep up with the leaders in Eugene.
She had been dropped completely with two laps left and ran 30 minutes 34.60 seconds with Great Britain team-mate Jess Judd 11th .
Ethiopia’s Letesenbet Gidey, the world record holder, took gold in 30 minutes 09.94 seconds.
“I felt I was getting back fit again and then I picked up a niggle with my hamstring five days ago,” said McColgan, who is still due to run in the 5,000m.
“I’m proud of myself to make the startline because there was a question mark whether I would or not. It’s frustrating, you ride the highs and lows. My build-up to this race hasn’t been as smooth as I would like and it knocks your confidence a bit.
“I’m disappointed with that. To come 10th again is disappointing, every year I feel I’m getting faster and improving and I’m still coming 10th. Mentally it’s tough.”
Andrew Pozzi reached the 110m hurdles semi-final after running 13.45 seconds in his heat to finish third and qualify automatically.
The 2018 World Indoor 60m hurdle champion said: “It was a very stacked heat for a first round but I ran a good race. It is encouraging to get into my running well after getting out of the blocks strongly.
“My body is in a really good place, and I felt really in control throughout my race. I kicked hurdle seven a little bit and then after that I made sure I stayed safe, didn’t hit any more hurdles and got to the finish line in a qualifying spot.”
He is joined on Sunday by team-mates Dave King, who ran 13.57 seconds in heat five, and Josh Zeller who clocked 13.41 seconds in heat two.
Aimee Pratt ran nine minutes 18.91 seconds for a new British record in the 3000m steeplechase to make the final but Lizzie Bird did not qualify.
Emily Borthwick and Laura Zialor could not progress to the high jump final while Nick Miller came 11th in the hammer final.
Earlier, Morgan Lake pulled out of high jump qualification to suffer more major championships heartbreak.
The 25-year-old caught Covid in Great Britain’s holding camp and, while asymptomatic, continues to self-isolate.
Last year she made the Olympic final only to withdraw with injury.
She wrote on Twitter: “Absolutely heartbroken to have to watch in my hotel room and, while I am grateful to be feeling 100% fine, it’s even more frustrating to know that I am physically able to compete but can’t.”
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