Gai Waterhouse is known widely as the first lady or the queen of Australian racing.

On Tuesday she earned the title that means the most - Melbourne Cup-winning trainer.

Little more than two decades after she gained her licence and on the 20th anniversary of her first Cup runner, Fiorente lived up to his favouritism in Australia's greatest race at Flemington.

In the early hours of Tuesday morning, Waterhouse's thoughts turned to her late father, TJ Smith, her mentor, hero and role model and the trainer of two Melbourne Cup winners - Toporoa in 1955 and Just A Dash in 1981.

"I thought of Dad this morning and how excited he would be," Waterhouse said.

The trainer's family, husband Rob and children Tom and Kate and daughter-in-law Hoda, celebrated the win with Waterhouse who many thought would become the first woman to train a Cup winner.

That honour went to Sheila Laxon in 2001 with Ethereal but Waterhouse never lost her ambition.

"It's been a burning desire of mine," she said.

"It's every trainer's dream."

Although she now competes on a level playing field at the races, it wasn't always the case and Waterhouse is proud of her achievements.

"Of course I'm proud that as a woman I've trained the Melbourne Cup winner," she said.

Waterhouse's bid for a licence was delayed by a protracted battle with authorities who denied her because her husband was a warned off bookmaker.

She took her case to the highest court and the Waterhouse Amendment to the Sexual Discrimination Act is her legacy with the ruling no-one can be discriminated against because of their spouse.

It's not the only battle Waterhouse has fought during her career.

She has been in the headlines a lot this year since a public fall-out with high-profile owner John Singleton.

Waterhouse trained most of Singleton's racehorses until the glamour mare More Joyous was beaten in the All Aged Stakes during the Sydney autumn racing carnival.

Singleton claimed Waterhouse's son, the bookmaker Tom Waterhouse, had told rugby league star Andrew Johns that More Joyous couldn't win the All Aged before the mare ran unplaced in the race.

Since she began training, Waterhouse has racked up around 120 Group One winners.

Rumours have been rife she is moving from Sydney to Melbourne or possibly heading to retirement.

So what ambitions does she have left?

"To become a better grandmother," she said.