The recent form of Streama has convinced trainer Guy Walter to give the mare a final chance for a Group One victory this season but he admits stablemate Skyerush would also be a worthy winner of the Tatt's Tiara.
The 1400m feature at Eagle Farm for fillies and mares is the last Group One race of the season and 29 horses will be vying for a start.
The winner of the Flight Stakes and Australian Oaks as a three-year-old, Streama has mixed her four-year-old form but her past two outings when fourth in the Doncaster Mile and third in the Stradbroke Handicap have shown her trainer she is somewhere near her best.
Skyerush has continued to step up to the mark this autumn with three Group wins from four starts and Walter is conscious Saturday's race could be her last chance to shine at the highest level.
"She's a seven-year-old mare now and whether she will come back next season is not certain," Walter said.
"But she deserves a chance to get a Group One.
"Streama will wear the blinkers like she did in the Stradbroke.
"I'm a little worried she might not have as much dash backing up after two weeks but she also deserves her chance."
Since her defence of the Group Two Emancipation Stakes on April 27, Skyerush has had a conditioning barrier trial and a raceday workout.
The mare has been raced sparingly in Group One races with her best result a fighting second to Pear Tart in the 2012 Tatt's Tiara.
Gai's Choice and Red Tracer, third and fourth respectively last year, are also among the entries as is 2011 winner Yosei.
The younger brigade is headed by Peron, the winner of six of her seven starts including Saturday's Listed Gai Waterhouse (1350m) at Ipswich.
Trainer John Thompson rates the filly higher than his 2012 winner.
"She's all over a better horse than Pear Tart and if she gets there in good shape next week she'll give it a shake," Thompson said after her Ipswich win.
"She's all class and she's shown that from day one."