Ridden by Rosie Napravnik and breaking from the far 13th spot, the overwhelming favorite in the $1 million race for 3-year-old fillies earned her third straight victory and fifth in seven starts. Untapable has won her last three by a combined margin of nearly 22 lengths.
Untapable stayed within reach of early leaders Sugar Shock, My Miss Sophia and Thank You Marylou before getting clear outside turning for home. The winner ran 1 1/8 miles in 1:48.68, the race's second-fastest time, and paid $4, $3.20 and $2.60.
My Miss Sophia returned $4.20 and $4.40, and Unbridled Forever paid $6.00.
Empress of Midway, partly owned by Louisville basketball coach Rick Pitino, was scratched after flipping in the gate.
"She was really great today," said Napravnik, who earned her second Oaks victory just two years after winning aboard Believe You Can. "We ended up in a great position from the outside post.
"She runs her best when she can get in a great stride. She relaxes so nice. She's growing up and is maturing. She is magnificent."
Untapable's dramatic finish followed some pre-race suspense involving two horses who violently balked in the gate.
The first was Empress of Midway, who sat down for a tense moment after flipping. Jockey Corey Nakatani wasn't hurt and stood by watching as workers quickly got the horse out; she walked away uninjured but was quickly scratched.
"She just went up in the gate and lost her balance and kind of sat down on her haunches and couldn't get herself back up in the right position," track veterinarian Larry Bramlage said afterward. "We didn't see anything obviously wrong and she's back to her barn."
Minutes after horses in surrounding gates were guided back in, second betting choice Fashion Plate also had issues before settling down. She hopped out of the gate and quickly fell behind in finishing 11th of 12 entrants.