When Big Brown turned for home, something wasn’t right. Jockey Kent Desormeaux knew the big bay colt was finished. Trainer Rick Dutrow Jr., who guaranteed racing’s first Triple Crown in 30 years, knew it, too. Big Brown straggled home last Saturday, losing the Belmont Stakes to 38-1 long shot Da’ Tara, who led wire-to-wire. Eased up in the homestretch, the 1-4 favorite was so far behind at the end that his margin of defeat wasn’t even charted.

Not once but twice, jockey Kent Desormeaux sneaked a peak to see if anyone was gaining on Big Brown.His big bay colt ran away with the Preakness on Saturday and now is pointed squarely down the path toward the Triple Crown.

The 3-year-old with the perfect record heads for the Belmont Stakes (ABC, June 7) in three weeks as the fourth horse this decade to try for the triple, a sweep last accomplished by Affirmed in 1978. The last to try was Smarty Jones in 2004.

Big Brown was pulling away from the field, accelerating with every powerful stride toward the finish line in the Kentucky Derby.

The crowd of 157,770 was on its feet and cheering as the big, unbeaten, muscular bay crossed the line first, 4 3/4 lengths ahead of the filly Eight Belles. Trainer Rick Dutrow Jr. was still celebrating, along with thousands of happy bettors, as Big Brown and the 19 other horses in Saturday’s race galloped out around the first turn at Churchill Downs.

It took a few minutes to sink in, but anyone watching those horses soon realized that one of them had fallen to the track. In just a few minutes, the joy of the Derby and the promise of a new Triple Crown season were upended when Eight Belles was euthanized by injection on the track.