Great Britain's Shanaze Reade suffered a suspected broken hand as a fall on the final bend of her BMX final ended her Olympic dream.
The 19-year-old, a double world champion who has not lost a race all year, had already crashed twice earlier in the competition - both times on the first bend.
She navigated that safely in the final but was understandably more cautious than Anne-Caroline Chausson of France who took the lead going into the second straight.
Reade narrowed the gap and tried to cut inside the Frenchwoman but could not hold her line and clipped Chausson's back wheel before hitting the tarmac.
Reade, who was taken away for x-rays in the British team car, said: "I'm hurting. I think I might have broken my hand and I'm cut all over.
"I'm only 19, there's so much more to come from me as an athlete. I feel like I might not want to see my bike for a while.
"I just caught the back wheel and went over. But I put everything into this race.
"I've fallen off and got back up, I've fallen off and got back up. I gave it my heart and everything, but today it wasn't good enough.
"I gave it the best shot I had and I didn't have any more."
British Cycling had paid out £30,000 to construct a replica of the Beijing track in Manchester, across the road from their national headquarters in the National Velodrome.
Performance director Dave Brailsford wanted her to practice on the unusually high start ramp they have out at Laoshan in the south west of Beijing.
The investment appeared to pay off as Reade started consistently better than any other rider but, having crashed twice there, it was the first bend which hurt her chances most.
Injuries allowing, Reade will next week head to Poland for the track cycling European Championships - an under-23 event where Reade will continue her velodrome education.
Having won a team sprint world title in partnership with Olympic gold-medallist Victoria Pendleton back in March, she is considering splitting her time between the two disciplines to increase her medal chances.