Richard Hannon has hailed Canford Cliffs as the best horse he has ever trained after injury forced connections to retire the colt to stud.
The four year old enjoyed a quite brilliant racing career, winning seven of his 11 racecourse starts and finishing either second on third on his other four appearances.
The son of Tagula first burst on to the scene with an electric performance in the Coventry Stakes as a juvenile and victory in the Irish 2,000 Guineas last season ignited a run of form which saw him win five successive Group One prizes.
The most notable scalp claimed was that of 14-time Group One-winning mare Goldikova in this year's Queen Anne Stakes at Royal Ascot, but his next start would prove to be his last.
The highly anticipated "Duel on the Downs" with Frankel turned into something of a one-sided affair as Frankel surged to a brilliant success, but Hannon and his team were left scratching their heads after Canford Cliffs' comprehensive defeat.
They subsequently found their star performer to be suffering from a pastern injury and have made the decision to call time on his racing career for fear of the problem developing into something more serious.
"He has a bit of a shadow on the joint running into the pastern and that could turn into something nasty - it could turn into a fracture," said Hannon.
"He's a perfectly sound horse and I could very nearly go on training him, but under that light, I don't want to do the horse any damage as he's done us so proud.
"It's a terrible shame - it's heartbreaking, but I don't want to see him end up with a bad injury.
"If we carried on, we would have to give him box rest and with a big horse like him, he'd just get bigger and bigger and heavier and heavier.
"Doing that might just cause him a bad injury and that would break everybody's heart.
"He now goes off to stud sound. If anything happened to him, I couldn't forgive myself.
"He's been a fantastic horse for the yard. He's won five Group Ones - you can't do any more than that.
"He was a very rare type in that he had such great early speed as a two-year-old but also stretched out to be a superb miler at three and four. He is without doubt the best horse I have had in over 40 years as a trainer.
"It's bitterly disappointing for his owners and for everyone here in East Everleigh that he had to be retired due to injury but at least it does explain why he hung so badly at Goodwood.
"Frankel might be a superstar, but we were looking forward to taking him on again in the QEII at Ascot.
"There is no way that Frankel would have given our horse the beating he did had we been right.
"Canford Cliffs did so much for us and we will all miss him, but we have the memories and the videos and, hopefully, we will have some of his sons and daughters back here at Herridge in the not-too-distant future."
Jockey Richard Hughes was adamant his mount was not at his best at Goodwood and feels this injury gives his theory plenty of weight.
"From day one I thought he was a star and it was lovely the way he showed it on the track," said Hughes.
"He's the best and fastest I have ever ridden and it certainly won't be easy to replace him.
"It was a little bit annoying how everyone was saying Frankel was too good for us. I knew in my heart and soul at halfway he wasn't moving.
"This problem must have happened during the race as he was nowhere near his best and he has still finished second."
Canford Cliffs is set to stand at Coolmore Stud in Ireland in accordance with a deal that was finalised at the end of last season.
The agreement meant the powerful operation owned a share in the colt for his racecourse appearances in 2011 and it also secured his services as a stallion.
Coolmore's MV Magnier added: "It's very unfortunate that he has been retired as a re-match with Frankel would have been a race to savour.
"But Canford Cliffs is an exceptional looking individual and he joins a select band of stallions to have won five or more consecutive Group One races.
"Ever since we bought into him last year many of the top breeders in Europe have shown a very keen interest in him, so I have no doubt he will be a very popular stallion."
* Press Association