Muir missed out on 1500m bronze by the slimmest of margins on Monday night but nevertheless turned up on Thursday for her second event, which would see her run her very first outdoor 5k race of the year.
The Scot kept pace with the field for the majority of the first heat but tired badly later on, coming home just under the 15-minute mark with the five automatic qualifiers well ahead of her.
She was left splayed on the track and appeared in serious discomfort, sparking fears in the commentary box that she might have been struggling with fatigue and mental exhaustion after the 1500m.
But after getting her breath back, Muir was able to speak to trackside interviewers and reckoned she had moved on from Monday’s disappointment.
“Mentally, I was fine. I just had to put the 1500m behind me,” Muir said.
“Reflecting on it, I was fourth in the world.
“I felt recovered from the 1500 but it was just the last lap that the legs just went. I’ve got three days to recover now.”
Muir has not had an ideal preparation for the championships, having suffered an Achilles injury just two months ago that left her unable to train for several weeks.
And it appeared to be taking its toll as fell away in the closing stages of the race.
“I was worried that maybe her Achilles was hurting her,” said former Team GB distance runner Paula Radcliffe.
However, Muir appeared to have no problems with injury afterwards and was optimistic she would be back on Sunday for the final.
“I went into this race really positive that I could get that automatic qualifying, so I’ll go into the final positive that I can do well there,” Muir added.
