Apple's Jade came with a devastating late run to catch the front-running Jer's Girl in the Knight Frank Juvenile Hurdle at Leopardstown.
Jer's Girl had them all in trouble turning into the straight under Robbie Power and looked set to maintain her unbeaten record.
Apple's Jade, the second string of two Willie Mullins' runners after Footpad, who finished third, was gaining approaching the last but still had a couple of lengths to find.
Jer's Girl was slightly hesitant and that gave Apple's Jade just enough of a chance and the 12-1 shot grabbed victory in the closing strides under Johnny Burke.
The winner was introduced into the Triumph Hurdle betting at 16-1 by BoyleSports, with the runner-up cut to 20-1 from 25-1.
Burke said of Apple's Jade: "She was fairly keen and just took a bit of time to pick up, but when she had something to aim at in the straight she was very tough and brave.
"She really stuck her neck out, and they are two tough fillies."