Trainer Gordon Elliott hailed Don Cossack as "the horse of a lifetime" after last year's Cheltenham Gold Cup winner was retired after suffering an injury setback.
Owned by Michael O'Leary's Gigginstown House Stud, Don Cossack held off Djakadam to win the most prestigious prize in National Hunt racing last March.
He subsequently suffered an injury when being prepared for the Punchestown Festival but had been working towards a return to action next month.
However, Elliott reported the 10-year-old to have heat in his leg, with connections opting to retire their star performer.
Reflecting on events last season and the quest to get Don Cossack back on the track, the trainer told listeners of RTÉ Radio 1’s Drivetime programme: “The horse was definitely sound after Cheltenham.
“He just gave himself a knock the week before Punchestown and, unfortunately, it just ruled Punchestown out and the rest of last season.
“We had him back in full work and everything was AOK.
“He just got a bit of heat back in the leg. Talking to Michael and Eddie and the whole gang, we just decided that the best thing to do for the horse was to retire him.
“When they come back after injury you know every day could be your last.
“We were very lucky to have trained a horse like him.
“He was the horse of a lifetime.”
Don Cossack had won six of his last seven starts, with his sole defeat coming when hitting the deck in the 2015 King George VI Chase at Kempton.
For Elliott, his Prestbury Park win will stand out as a career highlight.
“His best performance was probably his last run in the Gold Cup,” he added.
“It’s a shame he had to be retired, but it was a privilege and I was very, very lucky to train a horse like him.
“He’s a horse that will always be very close to me and all the staff.
“We’ll never forget him and we’ll be lucky to get another one like him ever again.”
Don Cossack's retirement means neither of the last two Gold Cup winners are in contention for the prize this year, with 2015 winner Coneygree ruled out of the race earlier in the week. However, Elliott will still be represented in the race.
“We have to look at Don Poli or Outlander, they’d be the two main ones this year,” he said.
“Don Poli was actually third last year to Don Cossack. He’s no bad horse.
“Outlander won the Lexus Chase at Leopardstown at Christmas. We’re in a good position, we’ve got a lot of good horses.”
Bryan Cooper partnered Don Cossack to win seven races, including the Gold Cup, and the rider admits that day will be hard to top.
He told 32Red: "He gave me the highest point of my career when we won the Cheltenham Gold Cup last March, and that day will take some beating whatever I now achieve in the saddle.
"I was actually beaten on my first three rides on him and he was a bit disappointing in his novice chase campaign after he won the Drinmore, but when I rode him on his return at Punchestown the following season after a summer break he was a lot stronger and a totally different horse.
"We knew then we had a horse with the ability to reach the top and his only defeats afterwards were a disappointing third in the Ryanair and when he fell when coming there with every chance in last season's King George.
"In my opinion, he was a 10-15lb better horse on good ground, and I think the formbook backs that up, too.
"He may have handled soft ground but that was just his huge natural ability getting him through it, and riding him on decent ground gave you a completely different feel and experience.
"I imagine it will be a long while before I sit on another as good as him.
"On his day he was outstanding, and at least he bowed out on a high on the racecourse."
Michael O’Leary paid tribute to those who had helped Don Cossack realise his potential, saying: "Anita, Eddie and I would like to sincerely thank Gordon, Karen, Louise and all the team at Cullentra House for the outstanding job they did in managing Don Cossack’s career, to ultimately win the 2016 Cheltenham Gold Cup.
"Gordon left no stone unturned to help Don Cossack return to defend his title but alas it is not to be. At the age of 10 we are all agreed that the best thing for “the Don” is a well-earned and very well pampered retirement in Gigginstown."