David Wachman's Stagemaster outbattled Kevin Prendergast's Rose Bonheur in a driving finish to the six furlong maiden at the Curragh.
The juvenile son of Johannesburg prevailed by a head at the rewarding odds of 16/1 under Colm O'Donoghue. Lechevalier Choisi was a neck further back in third.
Group 1 entered Petronius Maximus from the powerful Aidan O'Brien stable was sent off the 11/4 favourite but finished a disappointing 13th.
