Kent Desormeaux rides Big Brown to victory in the 134th Kentucky Derby Saturday, May 3, at Churchill Downs in Louisville, Ky. (Amy Sancetta/Associated Press)

Race favourite Big Brown came on strong down the backstretch to take the 134th running of the Kentucky Derby in Louisville on Saturday by nearly five lengths.

Big Brown, coming in at 2.5-to-1 odds, won despite drawing the unfavourable 20th and last post in the stacked 1¼-mile race, which took place on a clear day at Churchill Downs. The thoroughbred is now unbeaten in four races in its career.

Veteran rider Kent Desormeaux rode Big Brown to victory, his third Derby win. He also won with Real Quiet in 1998 and two years later with Fusaichi Pegasus. The winning trainer was Rick Dutrow.

The next outing in horse racing's Triple Crown is the Preakness Stakes on May 17, followed by the Belmont Stakes on June 7. It has been 30 years since a horse has won the crown, when Affirmed won all three races.

Dutrow confirmed that Big Brown would run in the Preakness, which would make him the seventh horse to come into the second jewel undefeated.

"We're ready to roll," he said. "I can't describe the feeling that all of us have right now.".

Eight Belles put down

Filly Eight Belles finished second but pulled up injured after the end of the race. She broke both front ankles and was immediately euthanized.

"There was no possible way to save her," on-call veterinarian Dr. Larry Bramlage said. "She broke both front ankles. That's a bad injury."

Eight Belles was trying to join Regret, Genuine Risk, and Winning Colors as the only females to win.

Jockey Gabriel Saez slid off when the horse tumbled but was not injured.

"When we passed the wire I stood up. She started galloping funny. I tried to pull her up. That's when she went down," Saez said.

Denis of Cork finished third.

Fourth place went to Tale of Ekati, owned by diamond mine magnate Chuck Fipke, who was hoping to have the third Canadian-owned horse ever to win the Kentucky Derby.

Sprinter Bob Black Jack, which has set track records over short distances, led for much of the first half of the race but fell back to 16th.

Race attendance was 157,770, the second-largest in Derby history.

With files from the Associated Press