Rail Trip ran well late to finish second, 2 1/4 lengths back, and John Scott completed an all-longshot trifecta that paid $1,950.70 for a $1 investment.
Tapizar, a 4-year-old Tapit colt, finished in 1:35.34 with Corey Nakatani riding for trainer Steve Asmussen.
The favorite, Shackleford, stumbled at the start and was forced to race from off the pace, contrary to his usual style. He faded through the stretch and finished seventh.
Tapizar won for the sixth time in 14 lifetime starts. He ran fifth in this race last year and in his last previous start had finished last of six in the Grade II Kelso Handicap at Belmont -- a race in which he suffered the same problems that beset Shackleford Saturday.