Aidan O’Brien believes he may have discovered a viable excuse for Japan’s disappointing effort in the King George VI And Queen Elizabeth Stakes at Ascot.

The Ballydoyle handler was hopeful his Juddmonte International hero would give John Gosden’s dual King George heroine Enable a run for her money in the midsummer highlight, but he was in trouble before the home turn.

As Enable cruised to an unprecedented third King George victory, Japan came home last of three runners, with his Irish Derby-winning stablemate Sovereign splitting the pair in second.

Speaking after saddling Japan’s full-brother Mogul to win the Gordon Stakes at Goodwood on Thursday, O’Brien said: “Japan came back a little bit sore from the King George.

“He had a bad stone bruise the following day, so maybe he was feeling that on the fast ground. These things take a bit of time to show up, but the next day he was very sore.

“Maybe that was the reason for his disappointing run.”