The Kentucky Derby has disqualified its unofficial winner, Maximum Security, for an alleged infraction that occurred during the race—the first disqualification of this kind in the history of the race.

The official Kentucky Derby Twitter account tweeted after the race: “For the first time in 145 years, the horse who finished first in the Kentucky Derby was disqualified.”

Maximum Security, a horse owned by billionaire philanthropist Gary West, had been the favorite in early betting and had previously won the Florida Derby. After objections, however, a horse named Country House, the 65-1 longshot, was officially named the winner. Only one other horse has ever been disqualified as the winner.

An objection review was filed by the team behind Country House, the number two horse. The review was called to determine if Maximum Security had bumped into Country House as the two horses were coming around the final turn. Country House was coming in hot for the lead as the horses ran into the stretch. The review lasted more than 10 minutes and changed the end of the biggest annual moment in professional horse racing.

Country House’s trainer, Bill Mott, answered questions about the disqualification during a winner’s press conference after the race.

“You always want to win with a clean trip... and recognize the athleticism of the horse... Due to the disqualification, I think some of that is diminished,” Mott said. “I know the stewards had a very very difficult decision... that being said, I’m damn glad they put our number up.”

Asked if race rules were possibly followed too closely, in light of the Kentucky Derby’s importance, Mott said he believed officials made the right decision.

“I think the Stewards, in my opinion, made the right call... if it was an ordinary race on a Wednesday they would have taken the winner down.”

When asked, Mott refused to place blame for Maximum Security allegedly interfering with the path of other horses on the jockey, Luis Saez.

Saez, a 27-year-old jockey with over 2,000 wins, won the Florida Derby on Maximum Security earlier this year.

“I think the horse did this on his own... I don’t think Luis Saez did anything intentionally,” Mott said. “Luis is a friend of mine, he rides with me, my heart actually aches for them—I’ve been on the other end of this plenty of times, just not in the Kentucky Derby.”