The decision to back-up Jessy Belle four days after an unplaced run at Flemington has been rewarded, with the mare racing to her first stakes victory in the Group Two Matriarch Stakes.

Jessy Belle finished fourth in a 1700m mares' handicap on Tuesday and co-trainer David Hayes said the decision to run her again in Saturday's Matriarch (2000m) came about after a suggestion from one of the mare's owners Jeff Allis.

"All credit to Jeff Allis, actually," Hayes said.

"She ran an even race earlier in the week in a weak race and Jeff said, 'is there any reason why she can't run, because I'd like to back her up and try her at 2000 metres'.

"And without that push I don't think we would have run her."

Jessy Belle had been stakes-placed on multiple occasions but Saturday's win was her first at black-type level and brought up a race-to-race double for the Lindsay Park stable and jockey Craig Williams.

William Buick had been booked to ride Jessy Belle but Williams got the call up when Buick couldn't make the weight.

Hayes said the instructions were to ride Jessy Belle quietly early to help her get the 2000m and he was impressed by the way the mare finished strongly from back in the field.

Jessy Belle ($26) chased down Sort After to win by half a length with Happy Hannah closing strongly late to finish another short half-head away.

Williams has only ridden Jessy Belle in four of her 42 starts but has won on her three times.

"She's been a really good mare to me," he said.