One hundred years ago, the immortal Man o’ War was in the process of winding down his undefeated 3-year-old campaign. Already, the fiery chestnut had cemented his legacy as a superstar of the highest caliber, shattering record after record while carrying high weights and crushing his rivals in one important race after another.

By the time Man o’ War lined up at Belmont Park to contest the Jockey Club Stakes — a 1 1/2-mile precursor to the modern Jockey Club Gold Cup — few owners were willing to run their horses against him. Why would they? Just one week prior to the Jockey Club, Man o’ War had annihilated the 1 5/8-mile Lawrence Realization, beating a single rival by 100 lengths.

Yes, 100 lengths.

The Jockey Club was supposed to mark Man o’ War’s debut against older rivals, but none were entered. “The Sir Bartons and Exterminators and Naturalists all ducked this super horse after they saw him kill off the best of his own class,” wrote W. J. Macbeth in the New-York Tribune of Sept. 12, 1920, dropping the names of the best older horses then in training.

In the end, only a fellow 3-year-old named Damask elected to join Man o’ War in the Jockey Club. The capable gelding was hardly a slouch; he’d already won the Louisiana Derby and would nab several more stakes wins in future years, eventually developing into a classy steeplechaser. Long distances were Damask’s forte, so the 1 1/2-mile distance of the Jockey Club figured to be a perfect fit.

And yet, horseplayers weren’t even remotely interested in betting on Damask. Their respective odds couldn’t have offered a greater contrast: Man o’ War was favored at a staggering 1-100, with Damask dismissed at odds varying from 60-1 to 90-1. Sure, Damask had stamina. But his fortitude would prove no match for Man o’ War’s speed.

Pre-race instructions called for jockey Clarence Kummer to ride a conservative race, restraining Man o’ War to avoid needlessly burning him out with another record-breaking performance. Kummer did his best to follow instructions, somehow holding back the superstar through modest fractions of :25 2/5, :49 3/5, 1:14 1/5, and 1:38 4/5.

But with half a mile remaining, Man o’ War was already in front by eight lengths, and he was incredibly eager to do more. “He was full of running and he gave Kummer such a fight in that first mile that he tired out the jockey, took his own head, and shattered the American record,” wrote Macbeth.

Kummer didn’t concede much, but Man o’ War took what he received and literally ran with it. He sped through 1 1/4 miles in 2:03 2/5, leaving Damask far behind, then blazed to the finish line in 2:28 4/5. Even under some degree of restraint — without ever being encouraged to actually run — Man o’ War had shattered the track record of 2:32 and the American record of 2:29 3/5. As penned by W. C. Vreeland in The Brooklyn Daily Eagle of Sept. 12, 1920, “[Man o’ War] ran the last half-mile so fast that he fractured the old record to smithereens.”

About the only record Man o’ War failed to break was the world record of 2:25, set in England two years prior by a horse named He. Yet it was widely believed Man o’ War could have trounced the world record too, if only he’d been asked. “There is no doubt Man o’ War … could have made He’s record look as obsolete as a coat of chain mail — a relic of the antiques, in fact,” opined Macbeth.

Man o’ War’s fast finish officially carried him to victory by 15 lengths over Damask, though the margin might have been larger. Some folks described the gap between runners as 20 lengths; still another described Man o’ War as winning “by about 80 yards,” which translates to 30 lengths.

The details might have varied, but the overall conclusion did not. Man o’ War had run an epic race in the Jockey Club, a fact reiterated when Damask returned four days later to finish second in the two-mile Autumn Gold Cup, beaten only a head by the great Exterminator.

Seventeen years would pass before Man o’ War’s own Triple Crown-winning son War Admiral broke his sire’s track record, clocking 2:28 3/5 to win the 1937 Belmont Stakes. And there’s no telling how long Man o’ War’s record would have stood if only — if only! — he’d been allowed to run his fastest.

J. Keeler Johnson is a writer, videographer, handicapper, and all-around horse racing enthusiast. A great fan of racing history, he considers Dr. Fager to be the greatest racehorse ever produced in America, but counts Zenyatta as his all-time favorite. You can follow him on Twitter at @J_Keelerman.