Melbourne apprentice Katelyn Mallyon has a gilt-edged opportunity in a Group One race, snaring the ride on Vain Queen in the Goodwood at Morphettville.

Vain Queen is an $11 chance in Adelaide's feature sprint on Saturday with Hucklebuck the $4.20 favourite.

The John Sadler-trained mare was the beaten favourite in the Robert Sangster Stakes on May 2 after getting back from a wide barrier.

"It's a great thrill to get the ride especially on a live chance as well," Mallyon said.

"She was unlucky I thought not to win last start.

"Hopefully we can draw a nice barrier and the horse seems to be going really well.

"It would be lovely to see her win a Group One as she really deserves it."

Vain Queen finished seventh from barrier 12 when ridden by Nick Hall in the Sangster, 1-3/4 lengths behind the winner Miracles Of Life and Sadler admitted he made a tactical error.

"The pace in the Sangster wasn't on," Sadler said.

"Not that I like riding her that way but I should have taken it up and gone forward."

Mallyon returned to riding late last month after aggravating an old back injury in a fall at Moonee Valley in February.

She recorded a double at Caulfield on May 2 including her first stakes win on Black Vanquish in the Listed Thoroughbred Club Cup at Caulfield.

Vain Queen will be Mallyon's second Group One experience with Gig her first in the Sir Rupert Clarke Stakes at Caulfield in September.

In 2011/12, Mallyon became the first female winner of the Victorian apprentices' title and claimed the junior premiership again last season.

In between titles, she was sidelined for nine months recovering from injuries suffered in a fall and her apprenticeship, which was to end on Saturday, has been extended until the end of the season because of the lost time.

The final field for the Goodwood will be declared on Tuesday.