The more Winx wins, the more the expectation grows.

Winx is the odds-on favourite to extend her winning streak to 21on Saturday in the Turnbull Stakes at Flemington.

The streak began in May, 2015 in the Sunshine Coast Guineas, a month after Winx finished second in the Australian Oaks.

Hugh Bowman is her regular partner and admits the pressure has grown with every win.

"Now every race is a pressure race really," Bowman said.

"I'll be perfectly honest, I didn't really feel it until this preparation because even up until the Queen Elizabeth Stakes win in the autumn she was doing it so comfortably.

"And I never felt as though there was a possibility of it happening, to be honest.

"And up until 15 or 16 wins it didn't really concern me if she did get beaten. For me it was about the process of getting her to peak on the big days.

"But now there is expectation that she will win and I'm like everyone else, I can't ignore that. It's certainly added more spice to the process."

Winx is at $1.15 for Saturday against a field of six other horses with Humidor at $4.80 and the only horse punters expect has any chance against her.

Trainer Chris Waller said everything had gone to plan with Winx in the build-up to the Turnbull, the mare's final race before her bid for a third Cox Plate.

Bowman has ridden Winx in two gallops at Flemington this week and is looking forward to Saturday.

In her three Sydney wins this preparation, Winx has had to overcome slow starts and has looked vulnerable before unleashing her unmatched finishing sprint.

Bowman admitted there was always the possibility she would be beaten.

"Obviously it's a reality we all have to be aware of," he said.

"That's what makes it so interesting. It's a horse race whenever she's running and things can happen. There's so many variables that we can't control.

"Obviously we don't want to see her get beaten, but if it happens we'll accept it like we do with every other horse.

"We'll analyse it - I'm sure everyone else will - and move on."