Coral Beach sprang a 16-1 surprise to win the Killavullan Stakes for Aidan O'Brien at Leopardstown.
Michael Hussey's mount bided her time in the seven-furlong Group Three contest, before picking up much better-fancied stablemate Old Glory and running out a one-length winner.
O'Brien's Old Glory, sent off at 2-1 second-favourite, broke well and set out to lead all the way under Seamie Heffernan.
He had a two-length lead into the straight but had no answer to Coral Beach's sustained run on the rail - with Jim Bolger's Guaranteed also staying on late to snatch second.
Favourite No Needs Never, on the back of his unexpected Listed win over Old Glory at Dundalk last time out, could never land a blow in the rematch and trailed in seventh.
Coral Beach had mustered just one maiden victory, on her penultimate start at Cork, from 11 previous attempts - and was consequently very much her powerful stable's second string here.
But she was a convincing winner nonetheless.
Winning jockey Hussey said: "She has plenty of ability, but she needs things to go right - and they did today.
"She travelled really well to the furlong pole - and when I went there, I think I got there a bit early.
"She's got her head in front now, and she knows what to do. There is improvement in her, I hope.
"You have to ride her with a bit of confidence. Seamie told me to ride her down the inside and don't come off the inside, so I stuck to that."