Long-shot Rich Strike stormed to victory at the 148th Kentucky Derby at Churchill Downs in Louisville on Saturday in one of the biggest upsets in the history of the race.

The chestnut colt, who went off at 80-1 odds, pulled into the lead down the stretch to edge favorite Epicenter, who was second, and Zandon, who was third.

Rich Strike only entered into the 20-horse race when Ethereal Road was scratched on Friday morning.

The unlikely victory was the first Kentucky Derby win for trainer and Kentucky native Eric Reed.

"I fell down in the paddock when he hit the wire," Reed said.

"I passed out. I'm so happy. This is the reason everybody does this. We're not supposed to be here but I knew this horse loved this track and he has been training so good all year."

Reed had considered walking away from the sport after he lost 23 horses in a barn fire in 2016. Thirteen horses were saved.

Summer Is Tomorrow and Crown Pride took the early lead in the blisteringly fast start of the race under cloudy skies and in front of more than 150,000 fans.

Epicenter looked poised to notch the victory until Rich Strike and jockey Sonny Leon made their move along the rail in the final seconds of the race.

"I knew the horse could do it if he could find his way through the traffic," Reed said.

"That's why I had Sonny on him. He got us here, he knows the horse and he gave him the greatest ride I've ever seen."

Rich Strike is the second longest shot to win the Run for the Roses after Donerail won at 91-1 odds in 1913.

Owner Rick Dawson was one of the few people who did not seem surprised by the outcome.

"We always felt like if we could just get into the race, we'd have a shot, and we proved it today," Dawson said.

"We've never entered a race we didn't think we could win. Ever. That's what Eric and I always talk about. If they are not ready to win, we'll take them back and train them some more."

Leon was forced to break from the No. 20 position in his first Kentucky Derby.

"We had a difficult post but I know the horse," he said.

"I didn't know if he could win but I had a good feeling with him. 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."

Rich Strike will now look to win the sport's Triple Crown when he competes at Preakness Stakes on May 21 and the Belmont Stakes on June 11.

This year's race was notable for the absence of Hall of Fame trainer Bob Baffert, whose horses have won the Kentucky Derby six times.

Baffert was suspended after last year's winner, Medina Spirit, failed a post-Derby drug test and was stripped of the title. Baffert trained Medina Spirit and has denied any wrongdoing.