Man o' War all-time greats with an "almost unbelievably brilliant performance" before a crowd of 25,000. At odds of 1-20, he faced only one rival, the well-regarded colt Donnaconna. Man o' War led from the start and Kummer let him run freely at the top of the stretch, allowing Man o' War to draw away by 20 lengths. Although eased in the final furlong, Man o' War set a world record of 2:14, beating the previous standard set in England by over two seconds and beating Sir Barton's American record by over three seconds. This time stood as the American record until 1961
Man o' War wife named the foal "Man o' War" in honor of her husband. Originally, the Belmonts intended to race Man o' War themselves. However, in the summer of 1918 with the ongoing war effort, they decided to liquidate their racing stable. At the Saratoga yearling sale, Man o' War was sold at a final bid of $5,000 () to Samuel D. Riddle, who brought him to his Glen Riddle Farm near Berlin, Maryland. The underbidder at the auction was Robert L. Gerry, Sr., who is reported to have said to his wife, "Forty-five hundred is enough to spend for any yearling."