La Collina collared Power close home to land a 33-1 surprise success in the Keeneland Phoenix Stakes at the Curragh.
Declan McDonogh brought Kevin Prendergast's filly with a devastating turn of foot to storm past Aidan O'Brien's runner in the last 50 yards.
Tough As Nails was third, and Lilbourne Lad was fourth.
David Brown's strongly-fancied Frederick Engels lost all chance when badly hampered by Parish Hall as he tried to make his bid about a furlong out.
McDonogh said afterwards: "This is a big lift for everybody. It's been a very slow start for the stable.
"They went hard and there was a bit of traffic at half-way. I just got out and was lucky with the clear run I got. I never got stopped. I just had to switch a couple of times.
"Johnny (Murtagh on Frederick Engels) went for a run on the fence and I was following him for most of the way and it (a gap) was closing from where I was looking at.
"I thought I wasn't going there, so I switched away from them and I'm lucky I did. I got outpaced early and let her find her feet.
She's a very good two-year-old and that was a true test. "She's all heart."
