Ruby Walsh on Kauto Star heads to the start before The Gold Cup at the Cheltenham Festival horse racing meet in Gloucestershire, western England, March 16, 2012. Reuters

Legendary racehorse Kauto Star was put down on Monday, a bitter end for many equestrian sport fans to the legendary champion’s high-profile racing career. The retired, two-time Cheltenham Gold Cup winner had recently suffered an injury, having fractured his pelvis and three bones in a stumble inside his paddock, according to the BBC.

The fall occurred on June 24. Officials described the horse’s condition as serious, and vets treating Kauto Star said he was in pain and that the best option was to euthanize him. Kauto Star was put down Monday afternoon, according to Eurosport. He was 15 years old.

"It is really devastating - he was looking fit and well at Laura Collett's yard,” the horse’s owner Clive Smith told BBC Radio 5 Live. Smith described Kauto Star’s main injury as being to his neck and spinal cord, which made it nearly impossible for the horse to stand. "He had a great talent for never giving up. He wanted to win…He had a heart of a lion,” said Smith.

Smith added that "the vets made him comfortable but the kindest thing was to euthanise him” and that he “did not suffer.”

The French-bred racehorse was trained by famed British horse trainer Paul Nicholls. Kauto Star’s racing career began in March 2003 at the Bordeaux Le Bouscat Racecourse in France, where he placed second. He made history when he won the King George Chase five times and won the Cheltenham Cold Cup in England in 2007 and 2009. Kauto Star was considered one of the most successful steeplechasers – a horse that races in competitions that require jumping over fences and ditch obstacles – of all time. He retired from racing in 2012.

"A wide range of sports fans, not just racing's, will be saddened by Kauto Star's death,” said Cornelius Lysaght, BBC’s horseracing correspondent. Twitter users were quick to show their condolences for the fallen hero.