Trainer Chris Waller will have to watch the replay of his 50th Group One win having closed his eyes when Winx almost came down in the Epsom Handicap at Randwick.

But after what looked like a disaster looming on the home turn, Winx and her jockey Hugh Bowman remained calm and powered to an impressive 2-1/4 length win over Ecuador in Saturday's $1 million race.

"It was an awful scrimmage turning for home. I admit I closed my eyes hoping for the best because all you hope is your horses come home well," Waller said.

Winx came home better than well to give Waller his third successive Epsom but surprisingly her jockey's first Group One win over the famous Randwick mile.

The mare started the $3.10 favourite with $26 chance Ecuador edging out Hawkesbury star Sons Of John by a half head for the runner-up spot.

"I don't like to get carried away but she got stood on her head at the 450 (metres) and then won with authority," Bowman said.

"I was 19 when I rode into the gates in the Doncaster for the first time, and it's just a privilege to be riding on this big stage and to ride a horse of this calibre and to win my first major Randwick mile."

Waller had been eyeing off the Myer Classic for Winx but her win has brought the Cox Plate into play as the list of contenders for the weight-for-age championship grows.

"There is a lot of water to go under the bridge but I think 2040 metres around Moonee Valley sounds attractive," Waller said.

"She is a very special horse and I think she might be even better suited to the Melbourne direction because she has a tendency to put head to the inside which would be reversed down there.

"You don't always know how they will make the transition from three to four years old but she has grown and come of age.

"And for her to bring up my 50th Group One, well that's something I'll go home and think about."

Waller has gone from strength to strength since his first Group One win with Triple Honour in the 2008 Doncaster and last season won 14 races at the highest level with 13 different horses.

Young trainer Jason Attard's first experience of Group One racing with Sons Of John was one he will savour.

"It doesn't matter what class he's racing against, he's honest and hits the line," Attard said.

"I thought he might have had (the race won) for a second."

He will consider a trip to Melbourne for Sons Of John with Ecuador's trainer Gai Waterhouse also heading south.

"It was a terrific performance," she said.

"We might push on to the Toorak Handicap or Crystal Mile and then the Mackinnon. I'm just not sure yet."