Outback Barbie ($5.50) has run unlucky thirds in the 2YO Classic and 3YO Guineas at the two previous Millions carnivals.
Gollan made it a race-to-race double after winning the Magic Millions Cup with Vega One.
"I can't remember a horse which deserved a big race win more than her," Gollan said.
"She was unlucky in both the two-year-old and three-year-old races.
"It is amazing she has not won more than four races but she will get her chance again in the winter."
Gollan accepted with Outback Barbie in the fillies and mares race and the QTIS Plate over 1300m.
"I had one look at the fields and took a second to run her in the Plate," he said.
Jockey James Mcdonald also got an extra buzz from the win.
"I rode her when she was third in the Guineas last year and she should have won," he said.