The winning owner of Rich Strike asked "What planet is this?" after the 80/1 shot produced one of the biggest Kentucky Derby shocks at Churchill Downs.

Rich Strike was only added to the 20-horse field on the eve of one of the most prestigious races in the world after Ethereal Road withdrew and went off as the biggest long shot.

Bought for only $30,000 last October and with only one win in seven outings, the rank outsider was expected to be an also-ran.

Yet the Eric Reed-trained Rich Strike bolted up on the inside with a blistering burst under Sonny Leon to become the second-biggest priced winner in the history of the Kentucky Derby.

Rick Dawson, owner of Rich Strike, could not believe what he had seen as a massive crowd of 147,294 caught their breath following a stunning upset.

"What planet is this? I feel like I have been propelled somewhere. I'm not sure," Dawson told Bloodhorse. 

"This is unbelievable. I asked my trainer up on the stage, I said, ''Are you sure this is not a dream? Because it can't be true.' He assured me this is real."

Trainer Reed was also in dreamland after such an unlikely success on the big stage.

"I don't know how [to put the win into words]," Reed said. "I fell down in the paddock when he hit the wire. I about passed out. I'm so happy.

"This is something, you know, is the reason everybody does this, because we're not supposed to be here, but I knew this horse loved the track, and we've been training so good all year."

Jockey Leon was not entirely surprised as he worked his way through the field to cross the line first.

"I didn't know if he could win but I had a good feeling with him," Leon told Bloodhorse. "I had to wait until the stretch, and that's what I did. I waited, and then the rail opened up.

"I wasn't nervous. I was excited. Nobody knows my horse like I know my horse."