Champion Kauto was the star that shone the brightest
Paul Nicholls spoke of his deep sadness after hearing the news his "champion of all champions" Kauto Star had to be put down due to injuries suffered in a paddock accident.
The history-making chaser suffered pelvic and neck injuries in a fall while relaxing in a paddock last week and despite the best efforts to save him over the weekend, connections revealed through that the 15-year-old had to be euthanised on Monday.
The 15-year-old enjoyed a glittering career with the champion trainer after being bought from France as a four-year-old, most notably winning the King George VI Chase at Kempton five times and becoming the first horse to regain the Cheltenham Gold Cup.
He retired from racing after pulling up in the 2012 renewal of the blue riband, having won 23 of his 41 races and over £2.3m in prize-money.
Later that year Kauto Star went on to pursue a career in dressage with Laura Collett.
"I was mortified when I heard. It's an extremely sad day. He was obviously a big part of the lives of everyone here in Ditcheat," said champion trainer Nicholls.
"I can say what I like about it, but it will not bring him back. You have to live on all those good memories.
"He was a champion of all champions, really, and I was very lucky to have him in a golden era.
"He was like my best mate. I saw him every day and he was a great horse in every way temperament-wise.
"When he left, it was obviously a big hole we had to fill in everybody's lives. He'd been so good for racing and so good for everybody.
"When something like this happens it's awfully sad, but sometimes things are unavoidable.
"He won 16 Grade Ones. I've been very lucky to have trained some incredible horses, but I've always said he's once in a lifetime. To be able to win from two miles, to two-and-a-half and three miles plus, he was awesome.
"He lived on the edge a little bit, he was one of those sort of horses."
Owner Clive Smith explained Kauto Star had suffered what appeared to be a minor injury last week but his condition deteriorated over the weekend.
During his short dressage career, Kauto Star took part in a demonstration on the opening night of the London International Horse Show at Olympia under Collett.
She said: "It's an honour and a privilege to have been involved with him and had him in the yard."
Ruby Walsh remembered Kauto Star as a "true heavyweight" following the death of the chaser he steered to 17 of his 19 victories in Britain and Ireland, including two Cheltenham Gold Cups and five King Georges.
The rider believes he should go down as one of the greatest National Hunt horses of all time, but that comparisons with Arkle are unfair.
"He had some hard races and took some heavy falls and kept coming back," Walsh said.
"He was a true heavyweight and it was a pleasure to be associated with him.
"I am too young to remember Arkle and it is very unfair to compare horses from different eras. To me in his era he was the best.
"He had the longevity and he won the most races and it is some feat to turn up and win any race five times, let alone a Grade One King George."
Walsh's association with the French import did have its blips, remounting after a fall in a three-runner race at Exeter in 2005, during which the 2-11 favourite suffered an injury and was also in the saddle when he fell in both the 2006 Champion Chase and the 2010 Gold Cup, but it is another race that Walsh will remember less fondly, a nose defeat to Our Vic at Aintree in 2008.
He said: "If I was to ride one race on him again it would the Betfair Bowl at Aintree.
"I went too soon on him that day, but that can't be changed. I loved riding him and enjoyed every day I rode him.
"He was lucky to get up when he fell in the Champion Chase and he was very lucky to get up in the Gold Cup. There were low points, but there were great points that he got up."
Recently-retired champion jockey Tony McCoy paid a glowing tribute to the superstar he rode in the delayed 2010 renewal of the King George VI Chase when he finished a disappointing third but was later found to be under the weather.
McCoy said: "It is very sad news. He was the greatest steeplechaser of the modern era. The record proves that.
"Winning five King Georges and two Gold Cups and winning the Tingle Creek over two miles is an amazing feat.
"He was great credit to Paul Nicholls as a chaser, to keep producing him time and time again.
"He didn't have it easy. He had an horrific fall at Cheltenham in the Gold Cup and to get him back and win another King George after that was an amazing feat.
"He had what a lot of those great racehorses have and those great sportsman have - a great will to win and a great heart.
"He was unbelievably tough as well.
"Ruby Walsh was brilliant on him. He was a horse with a lot of class and Ruby made him look like the amazing horse that he was. They were very well matched.
"Best Mate was probably the best Gold Cup horse we've seen since Arkle, because he won three of them, but to win five King Georges - I always thought Desert Orchid was the best horse I'd see in my lifetime, but Kauto Star achieved even more than him."