Triumph turned to tragedy when the 4-year-old colt Sailor's Cap, the upset winner of Sunday's Grade 3 Poker Stakes at Belmont Park, died suddenly in his stall there early Wednesday morning.\nThough Sailor's Cap spiked a temperature on Tuesday, the cause of death was not immediately known. The colt was sent to the New Bolton Equine Clinic in Kennett Square, Pa., for a necropsy.\nBarry Irwin, head of the Team Valor International syndicate that owns Sailor's Cap, said he doesn't usually order necropsies on horses, but did so this time because "this one is a mystery."\nIrwin said that Sailor's Cap had gotten sick on two occasions last year, including in November when he had travel difficulties when he shipped cross-country and back for the Hollywood Derby.\nIrwin noted that though Sailor's Cap ran well Sunday, he didn't think the horse looked as good physically as he had at his peak last year.\n"He looked like a horse that had already run and it was his first start," Irwin said.\nAccording to Jimmy Toner, the colt's trainer, Sailor's Cap spiked a temperature of 101 degrees on Tuesday morning. Sailor's Cap's temperature is usually between 99.4 and 100.2 degrees, Toner said. Toner said Dr. Don Baker treated Sailor's Cap, but a little while later the temperature spiked as high as 103, at which time "we got more aggressive with the treatments," Toner said.\nToner said he received a call about 3:30 Wednesday morning from his night watchman that the horse was having a problem, and about an hour later, Sailor's Cap was dead.\n"It's unbelievable," Toner said. "Usually, you have a situation where they get sick and it lingers. That wasn't the case."\nSaid Irwin, "You've got to love this game to be in it, to put up with all this crazy stuff."\nSailor's Cap, a son of Distant View, won 4 races from 10 starts and earned $616,970. As a 3-year-old, he won the Grade 3 Colonial Turf Cup.