The Makybe Diva Stakes at Flemington is an important race in the spring plans for Cox Plate favourite Mystic Journey but her trainer Adam Trinder is confident the star mare is again ready for the challenge.

Mystic Journey is the $2.20 favourite to stretch her unbeaten sequence to eight races in Saturday's 1600m weight-for-age race over a course and distance where she starred during the autumn, winning the Group One Australian Guineas and $5 million All-Star Mile.

The four-year-old made a statement in her season return, winning the PB Lawrence Stakes (1400m) on August 17 at Caulfield and Trinder says the mare has not missed a beat since after returning home to the trainer's Tasmanian base.

"I'd suggest she has taken really good improvement out of her first-up win," Trinder said.

"She will strip a fitter, more focused racehorse moving forward into Saturday.

"I think she's in really good order so she's going to give a really accurate account of herself. We're confident she's good enough and we're hopeful that's the case."

A field of 15 was declared on Wednesday with Mystic Journey drawing barrier 10 while Memsie Stakes winner Scales Of Justice has barrier nine and is $5 second favourite.

Mystic Journey is the $4.40 favourite for the $5 million Cox Plate (2040m) at The Valley on October 26.

Trinder has Mystic Journey in the nominations for the $7.5 million Golden Eagle (1500m) in Sydney, a new race this year restricted to four-year-olds and run a week after the Cox Plate, but the Cox Plate is his preference for the mare.

"If she's all well and her form warrants and suggests that she's going to be competitive in a Cox Plate that's definitely the direction she will take," he said.

"Obviously we've got a safeguard there of an entry in the Golden Eagle. So this is the race on Saturday that will give us clarity into which direction we push forward.

"If for some reason off the back of the Makybe Diva we don't feel that she's of the quality of a Cox Plate field she will diversify and head to the Golden Eagle. But at this stage it's just a contingency plan."

Trinder's preferred Cox Plate path is to run Mystic Journey in the Turnbull Stakes (2000m) third-up before the Cox Plate fourth-up.

"We've still got options if we feel she needs another run, she could go Underwood, Caulfield Stakes, Cox Plate. But I'd be surprised if I see anything to change my mind in that regard on Saturday," he said.

Mystic Journey will arrive in Melbourne on Friday morning and Trinder is looking forward to her running at Flemington again.

"She can just balance up and extend in a straight line with the long run in at Flemington," he said.

"She's unbeaten there so it will be great to get her back there."