The Ontario-bred daughter of Tethra overhauled Authenicat with 70 yards remaining in the 1 1/16-mile event to capture her first career added-money triumph. Victory Romance finished third.
Owned and bred by Knob Hill Stable, Nicki Knew won in a time of 1:44.82 on Woodbine's Polytrack surface. Kevin Attard was the winning conditioner.
Nicki Knew entered the Bison City off a fifth-place finish in the Woodbine Oaks, presented by Budweiser, which was her first-ever route attempt.
"I was very happy with the way this filly was going into the race," said McAleney. "Kevin had her so happy and in such good order. A happy horse is dangerous. I said to him this morning, 'I wouldn't trade horses with anyone.'"
In the trailing position after three-quarters of a mile, Nicki Knew began to pass fillies one by one on the second turn. Staying on strongly through the stretch, she rambled up to the flank of Authenicat and drew off late for a 1 1/4-length tally.
"We lost a bit of ground," McAleney said. "It wasn't an ideal trip. She had to be the best horse today."
Attard, who won last year's second jewel of the Canadian Triple Crown with Alezzandro, said he believed the homebred filly was a candidate for a route of ground.
"We were looking forward to stretching her out. She had trained well as a juvenile. At that time, we thought she would go long. Today, everything came to fruition," said Attard.
The third jewel of the Triple Tiara series is the 1 1/4-mile Wonder Where Stakes on July 26.
Nicki Knew returned $17.30, $9 and $4.10, combining with Authenicat ($5.10, $3) for an exacta worth $77.40. Victory Romance ($3) rounded out a $274.10 trifecta.
Skipping Queen, the 2-1 favorite in a field of seven, finished sixth.