Sretaw (11-1) ended a run of six seconds in style by taking the 21-runner Irish Stallion Farms EBF Irish Cambridgeshire at the Curragh.
There were lots in with chances in the final furlong in what proved a rough finish, but Wayne Lordan galvanised Gavin Cromwell's five-year-old to land the Premier Handicap.
Vastonea (16-1) was half a length away in second with the 4-1 favourite Hasanour third and Maggie Dalton (25-1) fourth.
"We were very hopeful. She's been second six times in a row and deserved this," said owner Eamon Waters.
"She's been running to her handicap mark all the time and kept going up, but in fairness to her she kept improving.
"I bred her and bought the mare for small money. It's nearly like a dream and I'm afraid I'll wake up.
"She's entered at Leopardstown on September 14 but it's up to Gavin where she goes."