Both fillies had raced once previously in maiden class, but jumped out of the ground in this tougher Black Type assignment over 1200 metres.
Flit, with Dwayne Dunn on board settled off the pace and charged to the line, kicking clear for what appeared a certain victory until Ready Set Sail flew out of the pack under strong riding from Damien Oliver to make a race of it.
They went to the line head to head with judge unable to separate the at the post.
"That's better than second," said Ready Set Sail's trainer Mick Price.
"She has that Group III win to go on the pedigree page now which is so important for these fillies.
"She'll go out now. She's a very scopey filly that will be a beautiful spring three year-old."
James Cummings has a good opinion of Flit and sees better things ahead for the daughter of Medaglia D'Oro.
"She's a good filly, she just jogged up to them and then was probably waiting for the others to get to her.
"Medaglia D'Oro fillies have had a good run for us of late with Tenley and Pohutukawa. They have the scope to keep improving."
Foaled and raised at Widden Stud for her owner breeder Bill Frost and his family, Ready Set Sail is the fourth foal and fourth winner from Fastnet Rock mare Jolie Brise, a good metropolitan winner that was fourth in the Group I MRC Thousand Guineas.
A half-sister to stakes-winner Rutherford Eagle and daughter of Group III winner Vestey, Jolie Brise has a weanling full brother to Ready Set Sail and was covered last spring by Zoustar.
Ready Set Sail is the 192nd stakes-winner for Vinery Stud's champion sire More Than Ready.
Flit is a half-sister to stakes-placed Flow and is the best of three winners from Group III placed Redoute's Choice mare Glissade, a daughter of Group III winner Steflara.
Glissade has a weanling filly by Street Boss (USA) and was covered last spring by Frosted (USA).
Flit is the 125th stakes-winner for Darley's super successful shuttler Medaglia D'Oro.