He won his third Cox Plate by the seat of his pants and now Hugh Bowman has handed them over for auction.

The signed and authenticated breeches, worn by Bowman as he rode Winx to a record-equalling third Cox Plate at Moonee Valley, will go under the hammer at the Call of the Card event on Melbourne Cup eve.

Winx won the race on Saturday by a long-neck from Humidor, a tighter run than her record eight lengths in 2016.

The winning bidder on Monday will choose the custom frame for the breeches and have a chance for a photo with Bowman while 100 per cent of proceeds will be donated to the National Jockeys Trust.

Australian Jockeys Association chairman Des O'Keeffe thanked Bowman for his efforts and generous donation.

"Hugh Bowman is a true champion both in the saddle and in his support of the National Jockeys Trust," he said.

"These signed breeches are now an incredible piece of Australian racing history."

Bowman, 37, has won 72 Group One races and four Sydney jockeys premierships over 18 years.

He's ridden Winx for 21 of 26 wins and is the only jockey to have won three Cox Plates in the history of the race.

WHAT BOWMAN ACHIEVED IN THE BREECHES:

* A record-equalling third Cox Plate for Winx

* A 15th Group One win for the Chris Waller-trained mare

* A Cox Plate record time of 2:02.94 in 2017

* An Australasian racing prize money record amassing $15 million

* Winx's 22nd consecutive win and 26th career win from 32 starts