Fans of the great SECRETARIAT recall with great pain that he famously lost the only three races he ever ran in his career that started with the letter "W": The Wood Memorial, The Whitney, and then the Woodward. Detractors of the great Triple Crown winner like to throw that fact in the faces of his fans as proof that he somehow wasn't as great as he seemed. Supporters of the horse point out that each of those losses was explained, not excused, but something very logical. However, because these reasons were not publicly disclosed at the time, the losses were devastating to the betting public and the legions of fans he had thinking that he would never lose again.
The Wood Memorial was then, as it remains to be now, a prestigious Kentucky Derby prep race run about 2 weeks before the big day at Churchill Downs, although in today's time some trainers shy away from it because they prefer their horses to have more time between their final tune up before the Run for the Roses. However, in SECRETARIAT's day, that was not much of a concern.
When Secretariat got ready to run in the Wood Memorial, it is worth noting that he was quite justifiably being touted as a superhorse. There had been no Triple Crown winner in 25 years entering 1973, and the sport was actually talking about changing the parameters to make it easier to accomplish. SECRETARIAT has been a unanimous choice for Horse of the Year in 1972, unprecedented then and now, he was syndicated for a then record $6.08 million before he even ran a race as a 3-year-old, and he had reeled off two emphatic wins in the Bay Shore and the Gotham Stakes on his way to Churchill Downs. The Wood Memorial was considered merely a formality.
However, the colt had painful abscess on the inside of his lip that rubbed against the bit whenever Ron Turcotte took a snug hold of him, which would cause him to throw his head back and lose momentum. For whatever reason, Ron Turcotte was not informed of the injury, and has said many times since then that had he known, he would have simply employed a tactic called loose-reining, and the big red juggernaut would have cruised on home to victory with ease, because Turcotte did say that the horse did, in fact, want to run.
As it happened, SECRETARIAT's stablemate, a horse named Angle Light, would go on to win the race that day, with a hard charging Sham just barely held off at the wire. This was the first time Sham would face Secretariat, and it was the only time that he would ever finish in front of him. Angle Light would never have a bigger win in his life, and in his stallion career he was advertised as a horse that beat SECRETARIAT. If I was a racing fan back then, without knowledge of the horse's injury, I too probably would have bought the whole media creation that he was just another Bold Ruler and couldn't go past a mile and win. But the thing is, he showed conclusively over his next 3 races that that was not the case!