Jasmine Mackintosh held off a late challenge by fellow north-east player Shannon McWilliam to become the first winner of the Stephen Gallacher Foundation Vase.
Mackintosh, a 16-year-old from Hazlehead, carded a last-round 75 at Macdonald Cardrona, near Peebles, for a winning two-over-par aggregate of 221.
She finished two ahead of McWilliam after the Aboyne player made up four shots in the last three holes in her closing 72.
"I'm glad that I've managed to win," admitted Mackintosh. "I played steady most of the way round."
Three clear of the field after opening rounds of 74 and 72, Mackintosh made birdie-2s at both the fifth and ninth in an outward 36, level-par.
One-over with three to play, she then finished bogey-birdie-bogey while playing partner McWilliam sandwiched an eagle-3 at the 17th between two pars.
"I not really thinking about how many shots I had in hand on the way round," added Mackintosh, whose previous biggest win came in the North of Scotland Girls' Championship two years ago.
Gullane's Joanne Free and Hazel McGarvie (Troon Ladies) finished joint-third on 227.