After an all-Australian win in the Melbourne Cup, trainer Danny O'Brien is already dreaming about the prospect of back-to-back victories for Vow And Declare.

Amid the euphoria of winning his first Melbourne Cup, trainer Danny O'Brien has not forgotten some words of wisdom from 'the Cups King' Bart Cummings.

Cummings told O'Brien: "There's only two guarantees in racing: bills and disappointments. And everything after that's a bonus.'"

The late Cummings enjoyed many "bonuses" during his legendary training career including winning a record 12 Melbourne Cups.

Cummings' advice is particularly apt given O'Brien's path to his biggest "bonus" yet, the $8 million Melbourne Cup.

Had he not fought and won a three-year, $1 million battle to clear his name over cobalt doping allegations, O'Brien would be serving out the final months of a four-year disqualification.

Instead, O'Brien is revelling in the Australian-bred, owned, trained and ridden Vow And Declare's victory against international Cup raiders.

"It's that sort of sport, that sort of industry, that it's a lot of years of hard work for many disappointments," O'Brien told reporters at his Flemington stables on Wednesday.

"You get pretty resilient but a day like yesterday certainly makes everything worthwhile."

O'Brien spent Tuesday night celebrating with family, friends and Vow And Declare's Queensland, NSW and Victorian owners, before happily showing off the trophy to his stable staff.

He is happy to have injected some Australian flavour into this year's Melbourne Cup.

"It's certainly a much more difficult race to win as an Australian than it was 10 years ago, let alone 20 or 25 years ago," O'Brien said.

"It's a very difficult thing to do, but it makes it incredibly satisfying when it happens."

Vow And Declare's 13 Australian owners include his Noosa-based "hobby breeder" and construction company boss Paul Lanskey, former NSW MP Geoff Corrigan and a number of first-time racehorse owners.

"It wasn't a horse that they had to go and spend hundreds of thousands of dollars on," O'Brien said.

"He was syndicated for $60,000 and now we've got real Australians that have got a unique experience that they've owned a Melbourne Cup winner."

O'Brien is already targeting the 2020 Melbourne Cup for Vow And Declare.

"He's only just turned four. He'll be a better horse next year and he'll need to be because he'll have to carry more weight.

"Ultimately it's a 3200-metre race that's on just across the road from where he lives and it's an $8 million race, so the most likely thing for us is that we'd try and see if he can win again."

Only five horses in the Cup's 159-year history have won the race twice - four of them winning back-to-back - including three-time winner Makybe Diva.

In his 16th Cup ride, jockey Craig Williams became only the eighth jockey to claim Australian racing's "grand slam" of the Melbourne and Caulfield Cups, Cox Plate and Golden Slipper.

"People always told me that it's life changing and, wow, it feels special," Williams said after completing the set with his Cup trophy.