For the first time in the famous race's 160-year history, no punters were on course at Flemington Racecourse as COVID-19 halted traditional festivities.

The usual crowd missed basking in the warmest Cup day in almost half a century, as the mercury topped 30.4C in the city.

The Bureau of Meteorology confirmed it was the hottest Cup day since 1969, when Rain Lover secured back-to-back wins.

It was also Melbourne's warmest day since March 19.

Unable to revel in the conditions on course, Melburnians flocked to pubs, restaurants and parks to watch $26 outsider Twilight Payment first past the post in the $8 million race.

Venues filled up quickly across the city in a much-needed post-lockdown boost, while one group in a park hooked up a TV to their vehicle.

St Kilda Beach was also swarming with people making the most of the hot weather.

Those who stayed home were allowed to have two adults from the same household visit for a party, with the carnival's rebadged Fashion on The Front Lawn encouraging people to dress up in their finest fascinators, frocks and suits.

Sportsbet reported over 5.5 million bets were placed on the big race, as more than a million Australians had a wager across the day.

A small number of owners were permitted on course at an Echuca race meeting under regional Victoria rules, while some Sydneysiders attended a low-key Cup day meeting at Randwick.

Twilight Payment's victory is the seventh Cup win for owner Lloyd Williams and the second for young Irish trainer Joseph O'Brien.

His father Aidan O'Brien finished second with Tiger Moth, while Charlie Fellowes-trained Prince Of Arran notched its third Cup placing.

One of Aidan O'Brien's other pre-race fancies, Anthony Van Dyck, was put down after suffering a fractured fetlock, prompting uproar from animal rights groups.

The five-year-old stallion is the seventh Melbourne Cup death in as many years.

Australian Associated Press