Laura Muir was reduced to tears after failing to reach the final of the 800 metres at the World Indoor Championships on Friday.
Muir was tipped as one of the team's brightest medal prospects following her performances this season, the 20-year-old Scot being ranked third fastest in the world in 2014 over both 800 and 1500m.
However, the veterinary student could only finish third in her heat and although she was promoted to second when Iceland's Anita Hinriksdottir was disqualified, her time of two minutes 2.55 seconds was not enough to advance to the final.
Muir did not recover from being blocked and lost ground as the athletes broke from their lanes after the first 50m.
She said: "I tried to start off quick to get a good position but I think I got a little bit caught out and because I was in lane one, the field came across and I got a bit blocked off.
"I lost a lot of ground, it was a case of trying to get back into position and I lost a lot of energy. Not only does the rest of the field get away from you, but you've got to work twice as hard to catch them up. You know you've got to win the race in the first place and you can't afford to lose that much ground. I just didn't have it in that final 200m when I needed it.
"I knew it was going to be very hard and I probably should have gone off a bit quicker, but I tried as best as I could. I knew getting into the final would be very hard, but definitely something I was capable of and I still think I am, it's just a matter of having a good race on the day.
"I'll learn from this and it's better to make a mistake now than in the future when there is a greater possibility of winning a medal."