Academic, driven by Justin Stein, set a new track record, winning the mile and one-eighth race at Woodbine in one minute 48.86 seconds — eclipsing the mark of 1:48.97 set by River Rush in the 2012 Plate Trial.
The Canadian-foaled three-year-old filly, a 66-1 outsider, beat out favourite London Tower by one and three-quarter lengths while Season Ticket came third, with Shez a Masterpiece in fourth.
"I didn't even have to ride her to the wire," said Stein, who was celebrating his first Oaks win. "The last few jumps I looked over and we had it wrapped up. Inside the 70-yard pole, I looked up and there was no one coming. I couldn't believe it.
"I knew we were going at a good clip, but she was real comfortable. She was relaxed but I had a lot of horse. At the three-eighths pole, when they came to her a little bit I just let her out a notch and they had to run hard to get to her there. At that point, when I opened her up again, she was going easy and had so many gears left."
It's the second Oaks win for trainer Reade Baker, who was first victorious in 2005 with an even money favourite, Gold Strike.