Blake Shinn has never ridden his Cox Plate mount Humidor, but the Sydney jockey knows exactly what he's up against in Australia's weight-for-age championship.

Shinn has benefited from Damian Lane's careless riding suspension at Caulfield last weekend to gain the ride on Humidor.

A two-time Group One-winner, Humidor is one of eight hopefuls attempting to stop champion mare Winx matching Kingston Town's three successive Cox Plate victories at Moonee Valley on Saturday.

Although logic suggests Winx will stretch her winning streak to 22 races, Shinn declared Humidor was not running to make up the numbers.

"I'll treat this race like any other one, I'm out there to win," Shinn said.

"You just never know, you're never out there to run second."

Shinn has crossed paths with Winx once during her Cox Plate-geared preparation and he rode Happy Clapper to a creditable second, 1-1/4 lengths behind the world's greatest horse on turf in the Group One George Main Stakes (1600m).

Humidor was an impressive winner of the Group One Makybe Diva Stakes (1600m) at Flemington last month, where he beat Winx's old adversary Hartnell by 3-1/4 lengths.

However, Humidor was no match for Winx when she debuted at Flemington in the Group One Turnbull Stakes. He finished third, 7-1/4 lengths adrift.

Humidor, who is backing up from a fifth in last week's Caulfield Cup, is on the third line of betting with Gailo Chop as a $19 chance.

"It was a good run in the Caulfield Cup I thought. Back to 2000, blinkers on ... he's certainly capable of running a bottler," Shinn said.