LEXINGTON, Ky. — Usually I want tension, I want drama in a horse race, especially one as important as the Breeders’ Cup Classic, which attracts the best horses from around the world and carries a hefty purse: $5 million, half of it to the winner.

But as American Pharoah and his seven rivals edged into the starting gate Saturday, the mist settled in the dark skies at Keeneland, and this historic racetrack in the heart of the Bluegrass State became deafeningly quiet. You could hear deep breaths. Nothing much was at stake — except the legacy of a horse and the definition of greatness.

“This was about American Pharoah,” said the colt’s emotional owner, Ahmed Zayat. “We wanted him to go out the right way.”

Sort of silly, right?

Well, not really when you take into account that horse racing is America’s oldest sport and that rare is the man, woman or child who does not become short of breath when watching a racehorse in full flight. In a world filled with smartphones, brain-rattling N.F.L. hits and presidential debates as spectator sport, there is something soothing and old world about watching a horse rocket around an oval ahead of others just because he can.