This Day in History: 1973-09-15

Secretariat won the Marlboro Cup Invitational Handicap in the then-world record time of 1:45 2/5 for 1 1/8 miles. He defeated his stablemate, Riva Ridge, by 3 1/2 lengths. The winner’s share of the purse, $150,000, made Secretariat a millionaire.