Katelyn Mallyon has claimed the biggest win of her career aboard Heatherly in the Group Two Rubiton Stakes.

And she is hoping to have the chance at an even richer prize aboard the filly later this month.

Mallyon, a two-time winner of the Melbourne apprentices' premiership, only recently became a senior jockey and made the most of her opportunity on light-weight hope Heatherly in Saturday's 1100m sprint at Caulfield to notch her first Group win.

With 51kg, Heatherly ($5) bounced to the front before scooting away rounding the home turn and she never looked in danger over the final 200m, winning by 5-1/2 lengths.

The Group One Oakleigh Plate (1100m) now beckons for the three-year-old in two weeks.

"It's something I've always wanted to do, ride a Group winner," Mallyon said.

"And obviously I want to get that Group One. Hopefully Heatherly can do it in the Oakleigh Plate if she heads that way."

Group One winner Politeness, who drifted from $3.70 to $6, led in the chasing pack hitting the line for second in her return to racing while Just A Bullet ($101) came in another three-quarters of a length away third.

"She was super impressive and was just in a race of her own from the start," Mallyon said.

"I knew we had it won from a long way out. She switched off early and I know if you can switch her off early she's got a really good finish on her. She just did it comfortably in the end."