On 23 May 1872, Don Juan made his racing debut as a two-year-old at
Morphettville. He finished unplaced over the distance of 12 furlongs (2,400m). Don Juan did not race as a three-year-old but was still nominated for the 1873
Melbourne Cup as a
maiden. This allowed the horse to be allotted a low weight of 6st 12 lb (43.5 kg). On 7 November 1873, Don Juan started the 3/1 favourite in the
Melbourne Cup and won by 3.5 lengths in a then record time for the race of 3:36.00. Days after the race protesters had made allegations against Don Juan and his win in the Melbourne Cup. The complaint was that Don Juan had been nominated and entered into the Melbourne Cup as a four year old, however was apparently over the age of four. The Victoria Racing Club found the allegations to be untrue. A day after winning the Melbourne Cup, Don Juan was successful in the
Royal Park Stakes at
Flemington. The next day he won the
Flemington Plate over a distance of 24 furlongs (4,800m). Don Juan raced once more on the 1 January 1874 when successful in the VRC Canterbury Plate over 20 furlongs (4,000m). In February 1874, Don Juan was on a training gallop at
St Albans Park, Victoria when he suffered soreness and blood was noticed in his nostrils. He was returned to his stall and reportedly died suddenly. An autopsy revealed internal bleeding and the cause of death was due to an inch long rent found in his heart. ==Pedigree==