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.
Big Brown was trying to become the first Triple Crown winner in 30 years. The 3-year old was racing with an injured hoof, which required special attention from a hoof specialist over the last week.
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 over the last three decades. The last horse to win the Triple Crown was Affirmed in 1978.