Verry Elleegant demolished red-hot favourite Incentivise to win the coveted Aus$8 million (US$6 million) Melbourne Cup on Tuesday in a party atmosphere as crowds returned for the "race that stops a nation".

With James McDonald in the saddle, the six-year-old mare came from behind in a thrilling finish to the gruelling 3,200-metre (two mile) handicap at Flemington, considered the ultimate test of stamina and staying power.

Incentivise, the shortest-priced favourite, at $2.90, since the legendary Phar Lap more than 90 years ago, was second some three-and-a-half lengths behind, ahead of Spanish Mission and Floating Artist.

Jockey James McDonald riding Verry Elleegant won the Melbourne Cup
Jockey James McDonald riding Verry Elleegant won the Melbourne Cup AFP / William WEST

"I love her to bits," an emotional McDonald said of his Chris Waller-trained horse, who came seventh last year and was priced in the betting market as an $18 shot.

"She's been so good to me. She's a superstar and I'm so proud of her.

"She was relaxed out there. She was relaxed the whole way. When I looked at the 600m, I was blowing kisses to her the whole way.

"I don't know. I just can't believe what's just happened. I never thought I would ever win one," he added after claiming the Aus$4.4 million first prize. "I always dreamed of winning one, but it's so hard to win."

Fans returned for this year's Melbourne Cup
Fans returned for this year's Melbourne Cup AFP / William WEST

It was a first Cup triumph for veteran Waller, who trained all-conquering mare Winx to 33 consecutive wins over a glittering four-year unbeaten streak before her retirement in 2019.

His racing stable simply tweeted: "You beauty."

The reigning Australian horse of the year, Verry Elleegant became the first mare to win the Cup since Makybe Diva in 2005 and defied history by carrying the greatest weight (57kg) to victory since Protectionist in 2014.

Jockey James McDonald was ecstatic at winning.
Jockey James McDonald was ecstatic at winning. AFP / William WEST

It was a major upset with Incentivise winning his last nine races, including the prestigious Caulfield Cup a fortnight ago, with few expecting him to lose.

But he had never competed over such a long distance and after being among the leading pack for much of the race, Incentivise began fading over the final 300m as Verry Elleegant came storming through.

The race was won in front of fans, who were back after one of the world's longest series of lockdowns recently ended, with cheers to the sound of popping champagne corks once more accompanying the thundering of hooves across the turf.

But it was still more muted than normal with only 10,000 vaccinated punters allowed under Covid rules, well under the usual 100,000 that pack the track.

They included Keith Foletti, who has been trackside for 85 out of 87 Melbourne Cups.

"I was christened at the Melbourne Cup in 1934 when the heavens opened up and I got drenched," he told broadcaster ABC.

"The only two years I've missed were the year I was on my honeymoon and last year when we were with the Covid."

The race was reduced to 23 starters after Future Score was ruled out after a late fitness test Tuesday showed lameness in his right foreleg.

Stricter veterinary checks have been introduced after the deaths of six horses associated with the Cup since 2013, including Anthony Van Dyck, one of the pre-race favourites last year who broke down with 500 metres to go.

First staged in 1861, the Melbourne Cup has been run on the first Tuesday of November since 1876, and the winning horse instantly becomes a household name in Australia.