Sir Winston has won the last leg of the Triple Crown in a 10-1 upset.
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Ten horses were scheduled to run the race, with oddsmakers picking Tacitus as a favorite.
The win gave trainer Mark Casse the final two jewels in the showcase for 3-year-old thoroughbreds. He won the Preakness with War of Will, who was expected to battle favored Tacitus in the 1 1/2 mile Belmont, according to The Associated Press.
Instead, Casse’s other colt took the lead after a ground-saving ride by Joel Rosario and held off Tacitus by a length. Longshot Joevia finished third, and Tax was fourth.
The Triple Crown grind caught up to War of Will, who ran in all three races. He finished ninth in the 10-horse field.
The Belmont capped an entertaining Triple Crown highlighted by a disqualification in the Kentucky Derby and a horse without a rider in the Preakness. It sparked interest in thoroughbred racing despite no possibility of the third Triple Crown winner in five years, coming on the heels of Justify last year and American Pharoah in 2015.
The second-place finish denied trainer Bill Mott two-thirds of the Triple Crown. His Country House was awarded first place in the Kentucky Derby.
Sir Winston paid $22.40, $8.80 and $6.10. Tacitus returned $3.90 and $3.20 as the 9-5 favorite. Joevia hung on for third, paying $8.70.
This unpredictable Triple Crown season started with a wild result in the Kentucky Derby. Maximum Security crossed the finish line first and become the first apparent winner to be disqualified, taken down for interfering with War of Will in the stretch. Country House was elevated to first, giving Mott his first Derby win and becoming the second longest shot (65-1) to win the Derby.
The Associated Press contributed to this report.