It was disaster for New Zealand middle distance runner Nikki Hamblin at her second world championships, falling in the preliminary rounds.
Competing in the heats of the 1500m at the championships in Daegu, South Korea, Hamblin was striding down the home straight for a top-six placing that would qualify her for the semifinals.
In trying to surge through a gap, she clipped the heel of a runner who had slowed slightly in front of her.
She walked to the finish in 4m 36.70s. Her heat was won by Hannah England, of Great Britain, in 4m 13.45s.
At the world championships in Berlin two years ago, Hamblin tripped and fell in the heats of the 800m and went on to excel in the 1500m.
Hamblin said she is an extremely aggressive runner and this may have been her downfall.
"All you care about is the finish line but by that point [50m out] we were so close together, you have to go for it, you always have to go for it. I hit the girl in front who was starting to come back a little bit and I was on the floor.
"I'm gutted - I fell over in Berlin first round, fell over here first round, fell over in Russia at the beginning of the year. I'm kind of reluctant a little to say that Russia was my fault, this one I'm not sure.
"What are you going to do? There's 50m to go and there are seven of you pretty much in a line, I think I was in sixth and I knew six had to qualify and I knew it would be close. Some girl starts tying up in front of you and what can you do? You can either stop and go round and lose three places or just keep trying, go for that gap and maybe I went a bit too aggressively for that gap."
The Delhi Commonwealth Games double silver medallist said she had been in top shape for the 1500m coming into the championships.
She will run in the heats of the 800m on Thursday.
"I didn't really want to be in that situation I've only run one eight this year, it wasn't pretty, it was pretty nasty - my workouts have been more towards the strength work of the 1500m - I'm gutted."
Meanwhile, Valerie Adams cruised through to tonight's shot put final.
Requiring a throw of 18.65m, Adams effortlessly sent the shot out to 19.79m as she seeks to win the world title for the third consecutive time.
Her arch rival Nadzeya Ostapchuk, of Belarus, also qualified with her first attempt of 19.11m.