Jockey Patrick Husbands kept the 3-year-old daughter of Sky Mesa settled in fifth early in the seven-furlong sprint, while Silent Serenity led the field of nine sophomore fillies through a quarter in :23 seconds flat.
As Youcan'tcatchme ranged up to grab the advantage for a half in :45.40, Spirited Miss commenced a four-wide rally. She surged to the lead approaching mid-stretch and held off the closing trio of Actionontwo, Katie Get Excited and Evil Kitten to win by 1 3/4 lengths in 1:23.48.
Actionontwo finished a neck in front of Katie Get Excited, with Evil Kitten a nose farther back in fourth.
Husbands, who has guided Spirited Miss to all three of her lifetime scores, knew he had plenty of horse.
"She's very classy," said Husbands. "It was only a matter of time before I pulled the trigger. She showed she was the best today."
Spirited Miss returned $9.70, $6.10, and $3.70 while Actionontwo paid $17.30 and $8.60 and Katie Get Excited brought $3.40. Evil Kitten, Youcan'tcatchme, Sky High Lady, Casa Loma, 3-2 favorite Man Stuff, and Silent Serenity completed the order of finish.
The victory completed a sweep of July 28 stakes at Woodbine for Oxley and the potent jockey-trainer combo of Husbands and Mark Casse. They won the Vandal Stakes earlier on the card with Uncaptured. Husbands has steered home eight stakes winners for Casse at Woodbine in 2012.
Spirited Miss, who entered the Duchess off a rousing allowance score on June 10, improved her record to three wins and a second in six starts. She is a Kentucky homebred out of the Horse Chestnut mare Little Hussy.