Jessica Ennis hit out at the officials at the Powerade Great CityGames as an embarrassing blunder denied her a personal best in the 100 metres hurdles on Sunday.
The heptathlete produced a fantastic run to win the race on the raised track on Manchester's Deansgate ahead of the Olympic champion and the world silver medallist, only to be told afterward only nine hurdles had been set out instead of the regulation 10.
Ennis clocked 12.75 seconds into a headwind to beat two of the best hurdlers in the world, Dawn Harper and Danielle Carruthers.
The time was 0.04secs faster than her previous best, but the organisational error meant it was invalid.
Ennis said: "I can't believe that. It's a great event, but that's a massive, massive mess-up.
"You expect that all the hurdles will be out and everything's the way it should be. You just run as fast as you can and get across the line and that's what I did, but unfortunately it wasn't set up right."
Nova International, the organisers of the event, appeared to lay the blame at the door of UK Athletics employees.
A Nova spokesman said: "We can confirm that due to human error only nine sets of hurdles rather than the required 10 were put out on the track for the women's 100 metres hurdles event this afternoon.
"We employ leading UKA officials to manage this vital element of the event on our behalf, and we will of course be investigating this unfortunate occurrence with them."
Organisers only confirmed the error about 30 minutes after the race, although Kelly Sotherton, Ennis' fellow heptathlete, was quick to point it out on Twitter.
The 2004 Olympic bronze medallist, who famously nicknamed Ennis 'tadpole' when the face of the London Games was an up-and-coming athlete, said: "That 100mh was great but I'm sure that there was only 9 hurdles not 10. Please someone verify!"
She later tweeted: "I feel bad! People probably think I'm being a cow bag!"
Ennis, who has lost her world titles indoors and out over the last nine months, will next weekend compete in her first heptathlon of the Olympic year in Gotzis, Austria, against her main rivals for gold in London.
She would still have won today's race even with 10 hurdles as she was pulling away from the rest of the field at the finish.
Harper was second in 12.86s with Carruthers third in 13.02.
The Sheffield athlete added: "I feel let down. I felt like it was a good race, I was running well, I was obviously coming through at the end.
"Stick another hurdle on there it would have been the same outcome. I'm so annoyed.
"I've still had a good competitive race, but I've just not got the result that I wanted.
"Maybe I'll have to save it for next weekend and check (the number of hurdles). I'll have to walk down the track and count.
"It's a great opportunity for me to come and race here, and it was a great race, but as an athlete you expect that everything should be set up properly and there should be no mistakes like that, so I am pretty disappointed with that."
Elsewhere, Dwain Chambers, racing for the first time in Britain since being cleared to qualify for the Olympics, received a warm reception from the crowd ahead of his 150m race.
The 34-year-old, who served two-year drug ban for testing positive for a banned steroid in 2003, finished second in 15.27, American Wallace Spearmon winning in 14.87.
World bronze medallist Andy Turner bounced back from finishing last in the 110m hurdles to win the 200m hurdles.
Christian Malcolm pipped Great Britain team-mate Mark Lewis-Francis to victory in the 100m in 10.46.
American Sanya Richards-Ross, one of the contenders for the 400m crown in London, won the 200m.
There was disappointment for Holly Bleasdale in the pole vault as she could only clear 4.43m for second place.