Group 1 Myer Classic winner Politeness (Street Sense) saw daylight too late but finished off strongly for second with 100/1 shot Just A Bullet (Danerich) a half-length back in third. (photo Grant Courtney)
"With the 51kgs she scooted along and we got nice easy sectionals early, she switched off lovely so gave a good kick and it was good to get a Group winner for them," Mallyon said.
Trained by Mathew Ellerton and Simon Zahra for Barry and Midge Griffiths, Heatherly was purchased for $90,000 from the draft of Broadwater Thoroughbreds at the 2014 Inglis Easter Yearling Sale.
The Group I Oakleigh Plate at Caulfield on February 27 is expected to be her next start.
"We've got her pretty right and it showed today," Ellerton said.
"She took a huge amount of improvement going into today.
"Let's hope we can go on in another fortnight.
"Three-year-old fillies haven't got a bad record in it (the Oakleigh Plate).
"All being well that's the way she'll head."
It was the third consecutive win for Heatherly and the fourth overall from seven starts taking her earnings to $275,950.
The 3yo daughter of Lonhro is the third foal of the unraced Danzero mare Dancing Heather who is a half-sister to Group 1 Stradbroke Handicap winner Linton (Galileo).
Dividing her time between New Zealand and Australia, Dancing Heather has a yearling filly by Cape Blanco (Ire) a filly foal by Helmet and was covered by Written Tycoon last season.
Heatherly becomes the 57th stakes-winner for Darley Stud's Lonhro who has six yearlings catalogued for the Premier Yearling sale and seven for the Easter Yearling sale.