Animal Kingdom comes from behind to win Kentucky Derby

(CNN) -- Jockeyed by a man who'd never ridden it in a race, Animal Kingdom made a late charge Saturday to win the 137th edition of the Kentucky Derby.

The colt's owners tapped John Velazquez to ride Animal Kingdom earlier this week, replacing jockey Robby Albarado after he got hurt while riding another horse.

Velazquez is a racing veteran, but his best finish in 12 previous Kentucky Derby tries had been second in 2001. He had been slated to ride this year's pre-race favorite, Uncle Mo, until that horse was forced out after developing a gastrointestinal illness.

"It was a loss for Robby, and a win for me," a bittersweet Velazquez told NBC in an interview broadcast throughout Churchill Downs after the race. "I'm very proud (of Animal Kingdom)."

The colt entered the Derby at 20-1 odds, starting from the outside from the No. 16 gate. It stayed in the back of the pack -- behind front-runner Shackleford, which ended up in fourth -- before pushing ahead around the final turn to cruise to a clear victory. The Kentucky-bred 3-year-old had run only a handful of races prior to Saturday, none of them on dirt.

"He's just kind of a magnificent animal," said Graham Motion, the trainer for Animal Kingdom. "This is an amazing horse, a very special horse."

Two horses with much better 9-1 odds -- Nehro and Mucho Macho Man -- finished second and third, respectively. The latter was trained by Katherine Ritvo, who overcame a debilitating heart condition and was trying to become the first woman to train a Derby winner. The pre-race favorite, Dialed In, was never a factor.

The wide-open race took place in front of 164,858 people, the most ever to attend the nation's longest continuously running annual sports event, a track official announced.

The 19 horses and their riders broke shortly after 6:30 p.m., all galloping around the 1.25-mile dirt course in hopes of taking home a $2.17 million purse.

According to the derby's website, more than $22 million was bet at the track -- topping last year's $21.5 million, with neither figure including many millions more wagered at sites outside Louisville.

The derby is the first leg of the Triple Crown, considered the most coveted achievement in thoroughbred racing. It is followed by the Preakness Stakes in Baltimore, Maryland, and the Belmont Stakes in Elmont, New York.

Animal Kingdom will now try to join the last horse to win all three -- Affirmed in 1978.

CNN's David Ariosto contributed to this report.