You said "he needed fast ground to be at his best" and any ground other than fast was his "achilles heel"
Here is his career form:
He ran 3 times on yielding ground - once easily winning a Group 1, once easily winning a Group 2, and the other time running 2nd in the English Derby at 12 furlongs to eventual 2-time Breeders Cup Turf winner High Chapperal - he was 12 lengths clear of 3rd place finisher (eventual Dubai World Cup winner Moon Ballad)
While his 11 length win technically came on good ground - it started to rain right before the race.
After his career was over - only an idiot would think he disliked wet ground. Horses who dislike wet ground get drowned over it on multiple occasions with no success.