Victoria Pendleton exceeded all expectations by finishing fifth on Pacha Du Polder in the St James's Place Foxhunter Chase at Cheltenham.
Pendleton gave the Paul Nicholls-trained nine-year-old a very patient ride and was stone last for the first mile.
As the race began to evolve, Pendleton, a double Olympic cycling champion, began to move through the field with style.
Dependable in the jumping department, Pacha Du Polder was making lengths at some fences but turning into the straight Pendleton still had plenty of horses in front of her.
As Nina Carberry brought Enda Bolger's champion hunter On The Fringe (13-8 favourite) through to beat Marito by a neck, Pendleton stayed on strongly to complete an afternoon to remember.
Pendleton, whose mount earned ?936 in prize-money for fifth, said: "I can't believe how nice the crowd has been, I'd like to thank Alan and Lawney Hill, Andy Stewart (owner) and Paul Nicholls, they've made this all possible.
"I feel honoured to have been given this opportunity.
"It's right up there with everything I've ever done, it's such a rush.
"Thank you to all the jockeys that have been involved today, they've all been so nice and I feel really lucky.
"I think it's one of the greatest achievements of my life, a special achievement."