Da' Tara went wire to wire to beat eight other thoroughbreds over 1½ miles, the longest and toughest of the three classics.
"I had no horse," said Big Brown's jockey, Kent Desormeaux.
All week long, Big Brown's trainer, Rick Dutrow Jr., said the horse's victory was "a foregone conclusion." He turned out be wrong.
The bay colt's disappointing performance followed convincing victories in the Kentucky Derby and Preakness. He failed on the same track where 10 horses had been beaten since Affirmed won the Triple Crown in 1978.
Dutrow was second-guessed all week about his handling of a quarter crack in Big Brown's left front hoof, which surfaced after the Preakness and wasn't patched until Friday. He also came under scrutiny after admitting using legal steroids on Big Brown, even though the colt's last dose was in April.
Big Brown was rank at the start and failed to respond when Desormeaux asked him to run in the last turn. At that point, Desormeaux eased him up.
The loss hit Desormeaux especially hard.
"This horse is the best I've ever ridden," he said. "Something's wrong, and I took care of him."
Desormeaux lost a 1998 Triple Crown bid by a nose on Real Quiet, and that ride was questioned throughout the business. Desormeaux struggled to get good horses and reach the same heights again.
Big Brown's path seemingly became easier when Casino Drive, considered to be his main rival, was scratched in the morning because of a bruised left hind hoof.