NEW YORK—Curlin became the first horse in North America to top $10 million in career earnings, winning the $750,000 Jockey Club Gold Cup on Saturday at sloppy Belmont Park.

The $450,000 winner’s purse pushed Curlin’s career bankroll to $10,246,800. Cigar held the old mark of $9,999,815, which stood for 12 years.

Curlin, the 2-5 favorite and defending Horse of the Year, beat Wanderin Boy by three-quarters of a length, with Merchant Marine finishing third.