The three-year-old daughter of D'wildcat won by 5 ½ lengths, her first win since taking last year's Victorian Queen Stakes by 5 ¾ lengths.
Originally slated for seven furlongs on the E.P. Taylor Turf Course, heavy rains in the Toronto area over the past few days saw the race contested at seven panels over Woodbine's Polytrack.
Turning for home, Authenicat, sent off as the second choice at 5-2, utilized a quick turn of foot to gain command at the top of the stretch and then opened up on her rivals down the lane.
Miss Juicey was second, while mutuel favourite Anne's Purse was third.
The final time for seven furlongs on the 'Poly' was 1:23.19.
"She's a talented filly," said winning rider Robert Landry, who celebrated his first Passing Mood triumph. "She's been sick and Josie (trainer Carroll) did a tremendous job to get her right. She was spot-on tonight."
Authenicat, owned by Vinery Stables and Fog City Stables, won her fourth race in what was her eleventh career start.
"We could hardly keep her on the ground yesterday and we had to gallop her this morning," said Carroll, of the chestnut Ontario-bred who has never contested a race on the grass. "She was just so full of herself. When she's like that, you know she's going to show up."
Authenicat returned $7.90, $3.50 and $2.50, combining with Miss Juicey ($4.30, $3.10) for a $38.20 exactor. Anne's Purse ($2.70) rounded out a $97.70 triactor.