Social media, predictably, erupted following news of the two deaths. But what was striking amid the shock and disgust was the number of people wanting nothing more to do with an event they had always associated with fun and glamour.
Thanks to the debate sparked by Tuesday's events, Australians are now contemplating unpalatable facts such as that most horses experience bleeding in their lungs during a race because, as an equine veterinarian told the ABC yesterday, they "are pushing themselves to the limit of biology".
That haemorrhaging is one of the causes of sudden death in racehorses; the other is heart failure. The burden on Admire Rakti's heart was exacerbated by the jockey's weight: 58.5 kilograms, the heaviest in the race.
For animal welfare groups, the sport is inherently cruel. They point to the dangers particularly of jumps racing, and to the many horses slaughtered each year because they can no longer perform the job they were bred for.
Opponents are also calling once again calling for the whip to be banned - although Racing Victoria says it played no role in Admire Rakti dropping dead in his stall.
While this year's Cup may prove a tipping-point in terms of public sentiment, the industry has gone into defensive mode, provoking yet more criticism.
In The Australian, not usually known for championing animal welfare concerns, sports columnist Patrick Smith was scathing yesterday about Racing Victoria's claim to have a safety record "equal to the best in the world".
"These are just words ... knitted together to protect an industry and not reflect reality," he wrote. "They are wasted unless they are matched by actions."
Last month an anti-racing group, the Coalition for the Protection of Racehorses, was attacked for mounting a massive billboard over a Melbourne freeway. The billboard featured an image of a dead horse and demanded: "Is the party really worth it?"
Increasing numbers of Australians are now asking themselves that question.