But Jim McAleney sent the Exchange Rate filly straight to the front and the pair never looked back, upending stablemate A Day For Dancing by 2 1/2 lengths. Georgia Song was another 1 1/4 lengths back in third. Odds-on favourite Royal Card was sixth.
The running time was a sharp :57.86 after splits of :21.86 and :45.37.
Steve Flint, Asmussen's assistant trainer, said the riding tactics were left to the jockey for each of the stable's three My Dear horses (Fanci Candi was fourth).
"We didn't give any rider any specific instructions," Flint said. "We felt all three fillies were capable of winning the race. (Juliet's Spirit) got a good break and when she got a breather on the turn, I wasn't really worried about her, but who was going to be second or third. We almost got it."
McAleney collected his second stakes win in as many days after guiding Nicki Knew to a win in the Bison City on Sunday. It is his third overall on the meet. "This filly is talented. Only time and distance will tell us how good she'll be. Right now, the sky's the limit."
Juliet's Spirit broke her maiden in a 4 1/2-furlong race on June 7 at Woodbine.
She paid $17.70, $7.40, $5 across the board and combined with A Day for Dancing ($5.20, $5.40) for a $49.20 Asmussen exactor. Georgia Song ($6.60) rounded out the $546.90 triactor. The $1 Superfecta, with Fanci Candi, paid $2,175.90.