Hall of Fame jockey Calvin Borel has engineered his share of upsets on the big stage, perhaps most famously guiding Mine That Bird to a stunning, rail-skimming 50.60-1 score in the slop in the 2009 Kentucky Derby.

Borel’s win aboard Rockamundo in the 1993 Arkansas Derby must rank right up there with the biggest shockers ever on the Kentucky Derby trail.

“We understand that anyone that reads the [Daily Racing Form] would’ve thought we were crazy to run this horse,” owner Gary West on Rockamundo’s participation in the 1993 Arkansas Derby.

The bay colt by Key to the Mint flashed some promise as a 2-year-old for trainer Orin J. “Benny” Glass Jr. and owners Gary and Mary West. He won only one of seven starts but finished in the top three in a trio of stakes, including a third-place finish in the Grade 2 Arlington-Washington Futurity.

Rockamundo closed out his juvenile season in the Rhythm Stakes at Gulfstream Park and was beaten by only a half-length while fourth in the one-mile and 70-yard race on the Breeders’ Cup undercard.

Unfortunately, Rockamundo showed little in his first two races as a 3-year-old. He was 11^th and beaten by 11 lengths in the Louisiana Derby and then was unplaced and beaten by 10 ¾ lengths in the Remington Park Derby. So, while Rockamundo had shown some ability as a 2-year-old, he had been drubbed in both starts at 3 and owned only one win (in Nebraska) in nine starts entering the 1993 Arkansas Derby. He was one of only two entrants in the 10-horse field sent off at more than 30-1 odds and the longest shot in the field at 108-1 April 17 at the Hot Springs, Ark., track.

“We didn’t take any of it personally,” Gary West told BloodHorse. “We understand that anyone that reads the [Daily Racing Form] would’ve thought we were crazy to run this horse.”

A deep closer in his previous nine starts, Rockamundo was paired for the first time with Borel in the Arkansas Derby. Borel said he “was stunned” when Rockamundo showed uncharacteristic early speed while racing within a length of pacesetter Foxtrail.

“When I knew I had a lot of horse left at the half-mile pole, that’s when I started getting pretty confident,” Borel said.

After setting a swift pace through a half-mile in :45.82 and six furlongs in 1:09.95, Foxtrail began to tire and Borel guided Rockamundo through an opening on the inside to take command. He celebrated with a passionate shake of the whip as Rockamundo crossed the finish line a length and a half in front while many of the 70,002 in attendance watched in disbelief.

“This is absolutely my greatest thrill in racing,” said Glass, then 44.

Borel winning 2009 Kentucky Derby on Mine That Bird. (Eclipse Sportswire)

Borel was a 26-year-old who at the time had never started in a race at Churchill Downs, but in the years to come the Louisiana native would win more than 1,200 races at the iconic Louisville track with Kentucky Derby victories aboard Street Sense (2007), Mine That Bird (2009), and Super Saver (2010).

Rockamundo and Borel finished 17^th in the 1993 Kentucky Derby, won by Sea Hero, and the Arkansas Derby winner did not visit the winner’s circle again in seven unplaced finishes after his monumental upset.

“If it was a fluke, it was a nice fluke” Glass said after the Arkansas Derby.

Indeed, it was.