Declan McNamara got the perfect boost ahead of stable-star Mossey Joe s run in the Galway Plate Trial at Down Royal when Miss Mary Mac claimed the beginners chase on the card.
John Cullen sent his mount to the front at the second last and she galloped on strongly to settled matters before the last.
The mare went on to record a 13-length victory over Hazeymm with 2/1 favourite Our Gar back in third.
It was the first start over fences for the seven-year-old, who had won twice in bumpers and hurdles and had also taken two point-to-points.
"She's a very good mare when she is right," said McNamara afterwards.
"I was afraid of the favourite Our Gar. It's a pity my father (who owns her) wasn't here tonight but he's visiting his sister in Kent."
