So You Think has been retired to stud in Australia after lameness ruled him out of the Coral-Eclipse at Sandown on Saturday.
The Aidan O'Brien-trained six-year-old would have been aiming to land back-to-back renewals of the Group One contest over a mile and a quarter, which was due to be his final run before returning to his native Australia.
So You Think had been in outstanding form this season with consecutive Group One victories in the Tattersalls Gold Cup at the Curragh and the Prince of Wales's Stakes at Royal Ascot.
O'Brien said: “So You Think is an extraordinary horse and it was a real privilege to have had him here at Ballydoyle on loan from Australia.”
Formerly trained in Australia by the legendary Bart Cummings, for whom he won two Cox Plates, So You Think moved to O'Brien's Tipperary base after Coolmore bought a controlling interest.
He was to add five Group One success to his CV under O'Brien's care, to go with the five he claimed Down Under.
Coolmore's Tom Magnier said: “It's a big disappointment that he'll miss the Eclipse, but he's had a wonderful racing career and now it's time for him to shine at stud.”
Following last month's Prince of Wales's Stakes win, O'Brien gave a frank assessment of the horse's career since arriving in Ireland, blaming himself for some of his defeats and only recently moving back towards the principles from So You Think's time in Australia.
O'Brien said after the Ascot win: “I think we've had him a year and a half and it's taken me that long to learn how to train him.
“We were working him too long, too hard and too often. I’m sorry it took me so long to get him back to where everyone said he was.”