Bookmakers gave horse and trainer little hope as he took on big names including Messrs Nicholls, King and Fry.
See the full result here: 100-1 Samuel Jackson
Richard Mitford-Slade, 52, confirmed: “It’s my first runner under rules – I got my permit only 14 days ago. This is my local track so I thought I'd run him here in the hottest hurdle I could find!
"I had a little bit on, although I’m not a gambler. I knew he was a good horse but he was training only with point-to-pointers so I didn’t know how good. He’s class, isn’t he?
“I’ve always had point-to-pointers and thought it was time to run some under rules. The big question is what I do next with him.I’ll show my ignorance by saying I’ll have to go away and look in the programme book."
Mitford-Slade runs an equestrian business has just four runners under rules.
Samuel Jackson, named after the actor, is a homebred. Mitford-Slade said of the name: ''My wife is a fan of the actor.''
The gelding's breeder Lucy Fielding-Johnson said: ''I can't talk. I was shouting for him. It was totally unexpected.''
Jockey Michael Nolan said: ''This is a really nice horse. That's the first time he has run under rules but rode like a seasoned campaigner.