Two horses, Alan Breck and Leighton, were leading Humorist at the mile, but now Donoghue was ready to make his move. As the jockey had expected, the long grind had slowed the speed horse Leighton and, as he faltered, Humorist moved into second position one length behind Breck. Humorist was still running well within himself, but Donoghue dared not call on him for more speed at this point. The colt was not all out, yet Steve sensed that he had little in reserve. His smooth action had roughened slightly in the last eighth, enough to warn his experienced rider that he might come to grief in the stretch drive.
It was the habit of Alan Breck, another speed horse, to bear out when he was tiring. This fact presented Donoghue with a tricky tactical problem. If he went out with Breck as the latter drifted, he would lose priceless ground that he could never get back at this stage of the race. If he went inside, he could gain ground and perhaps the winning edge in a tight race—provided that Breck did indeed go into his outward drift.
Watching the leader closely, Donoghue saw Breck flip his tail in the jerky motion that betrays a weary, discouraged racehorse. Momentarily now, according to his past form, Breck should drift out from the rail—but Steve could not wait for that to happen to make his move. To ensure that vital edge, he must gamble on Breck following his usual racing pattern, and so, boldly, Donoghue guided Humorist for the opening that had not yet appeared. The colt hung for a tense instant—then came willingly. As he reached the leader's tail, Breck, as if on cue, moved out from the rail just enough to let Humorist through. The cool gamble had paid off.
Leading the field now, Donoghue used all his racing skills to keep Humorist from running himself out in the stretch, which at Epsom turns into an uphill ordeal for the last 300 yards. Humorist came into the stretch two lengths in front. Now came the last and greatest challenge. Moving up fast on the outside, driving past fading horses, came late-running Craig an Eran, with Jockey Brennan whipping hard. Eran had beaten Humorist in the Two Thousand Guineas. Now, on the longer course, Brennan was confident that his powerful stretch runner could win again. Eran drew even with Humorist's saddle girth, gradually moved up until both colts were eye to eye. Then, as they approached the finish, Humorist inched ahead and won by a neck.
After that great victory in the Derby, Humorist was allowed to rest two weeks at his home barn at Wantage. Entered in a minor race at Ascot, the colt was scratched on the morning of the race, when Morton discovered flecks of blood inside Humorist's nostril after an easy work.
Morton immediately sent the Derby winner home. The colt appeared perfectly well upon arrival, but the stable vet was called in to examine him as a routine precaution. As before the Derby, the vet found nothing wrong.
Several days later Jack Joel engaged A. J. Munnings, the noted painter of thoroughbreds, to do Humorist's portrait for the famed Gallery of Derby Winners at the Newmarket Jockey Clubhouse. Munnings worked on the portrait all one morning before going to lunch. Returning, the artist found Humorist lying dead in his stall. Blood from the colt's mouth and nostrils stained the straw bedding around him.
Two veterinary surgeons performed an autopsy upon Humorist's body. The operation disclosed that the massive hemorrhage which killed the colt had resulted from advanced and long-standing tuberculosis. The tissue of one lung was completely degenerated and that of the other had been severely affected by the disease. Shocked at the news of Humorist's death, Donoghue paid him a horseman's tribute. "He gave me everything he had when it must have been agony for him," said the jockey. "No horse ever showed greater courage."
After Humorist's death, the racing fans who had branded the horse a quitter were—as turf writer Joe H. Palmer later sardonically noted—"somewhat abashed, a few of them for as long as 10 minutes."