The lowering black clouds rumbled and dipped ever deeper; the sun weakly tried to break through but all too often was eclipsed.

It was a spring day that felt like the depths of winter. But in the end the weather and climate proved prophetic.

The rain-soaked and wind-blown crowd at Moonee Valley had come to witness the coronation of a champion.

Her formidable deeds over the past 18 months have stamped her as a racehorse of legend, but  what she accomplished when she destroyed one of the highest class fields assembled for Australia's weight-for-age championship was  beyond the imaginings of even her most fervent fan. 

To win a second Cox Plate is not unique. But to do so in the fashion that she and her faithful partner Hugh Bowman did on this bleak  Saturday was extraordinary.

Never has the heavyweight event been won by eight lengths before, and that is being generous. Bowman began to ease her down with the line in sight, and it is frightening to think quite how great her winning margin could have been had her jockey pushed her out.

Before the great race there were those who prophesied that this might be the test that finds out  this champion.

Hartnell, the tough six-year-old gelding from the Godolphin camp, had been imperious all spring  and he looked, at least on  form, as though he finally had the opportunity to balance the ledger against his female nemesis.

Some chance.

Winx had beaten him on three  occasions, and that run has now stretched to four, the last triumph the most imperious.

For Chris Waller, her trainer, these are emotional days.

The New Zealander is one of the great  stories in Australian racing, a man who arrived here almost 20 years ago with a little money, some support and  full of dreams and ambitions.

But never in his wildest imaginings, when he was poking around at Kembla Grange and Wyong watching on television as Sunline, that great New Zealand mare, was winning her two Cox Plates , that he would one day be in charge of a mare that is Sunline's equal, and perhaps her superior.

Waller is quick to show his feelings. Not for him a stiff upper lip. His is more the quivering kind.

His voice cracks and quavers, he fights to hold back the tears, his body seems to tingle and tremble as he seeks to take in the enormity of his mare's accomplishment, the scale of her achievement.

Waller has spoken publicly on numerous occasions of the pressures of training a horse  who, like the greats before her – Black Caviar most recently, Makybe Diva, Might And Power, Sunline – have become crossover equine athletes, beloved of the public, gallopers who transcend racing and become the stuff of  Australia's sporting narrative..

It is, he says, like training a horse for the whole country, with everyone wanting to know about her wellbeing in minute detail.

It's the kind of attention that most trainers would shy away from, but this quiet Kiwi is happy enough to deal with it  for the rewards that it brings and the place in destiny it affords him.

And he is set to subject himself to the same microscopic examination for the next 12 months as he immediately declared Winx would seek to join racing's immortals by winning a third Cox Plate in 2017.

Yes, there are the glamorous invitations from Hong Kong, Dubai and a place before the Queen at Royal Ascot. And of course they are, for Waller and connections, very tempting.

But he knows that he owes what he has to the Australian racing industry, and the Australian public.

Winx does not have to be only a hometown heroine, but Waller is happy for her to repay the affection and faith of the Australian public by continuing to run her here.

"You respect the Australians, they respect her. That [a third Cox Plate] will be right up there at the top of our pecking order, " he said in the first flush of victory.

"I don't want to go overseas for one race ... maybe the world will come to us," he said,  throwing out a warning. "We were just in the zone today, the whole preparation has been perfect. Wherever she goes, if she's in that zone, she will beat anything in the world."