Rich Strike produced a sensational 80-1 upset to win the Kentucky Derby at Churchill Downs.

The Eric Reed-trained colt only made the field on Friday with the scratching of Ethereal Road, but powered home from an unpromising position under Sonny Leon to stun favourite Epicenter and Zandon.

The winner had just a couple behind him entering the back stretch, with the first half-mile run at almost sprint speed.

Leon made his move rounding the home turn on the outside of Mo Donegal, edging his way through traffic and finding a lane on the inside rail, before cutting to the outside of Messier to lunge late and deny Steve Asmussen's Epicenter, who had taken over at the top of the stretch. Zandon was third.

It was a fairytale success for Reed, who lost 23 of his horses in a fire at his barn in 2016.

"I fell down the paddock when he hit the wire, I'm so happy. This is why everyone does this – we're not supposed to be here, but I knew this horse loved the track and he'd been training so good all year," he told NBC Sports.

"Sonny Leon – they know who he is now."

Owner Richard Dawson said: "We'd never put a horse in a race we didn't think we had a chance of winning, I promise you.

"We just knew we had a shot, because every time he went longer (in distance), he got better. Today we went a mile and a quarter and he kept going.

"Eric is the reason I'm in the industry right now, I was ready to get out. I was disenchanted with the whole thing, but I met Eric through a close friend and I thought 'you know what, I like this guy and I'm going to give it another shot'.

"It's been nothing but a great ride since."

A jubilant Leon said: "Well I'm feeling really happy, you don't know how excited I feel. I brought all my family with me, my daughter's first time at the Kentucky Derby, the first time for me and we did it

"I know my horse, I know I had a horse for this race, I didn't know if he would win the race, but when we were in the race in the final furlong in the last (part of the race) I can feel my horse was tough, he was tough

"Wow, I tried to be nice and easy and race in the back (of the field), and that's what I did, when we were turning for home I found a bit of traffic, but I never panicked, I waited for my moment and came through in the stretch and I said to myself 'I think I got this, the Kentucky Derby'.

"It was amazing – amazing, especially the way we did it, in the last 50 yards, it's a dream come true."