Nine-year-old Charley Hull defied driving winds to win the Ladies' Golf Union's Health Perception championship at Turnberry.
Kettering's Hull scored 28 stableford points then won at the second play-off hole against Janice Cloran, 46.
There was an initial entry of 24,000 players from nearly 1,300 clubs across Britain and Ireland.
"I first swung a club when I was two. I'm so excited. I can't believe it," said Hull, who has a handicap of 26.
She will now tee up with one of the world's leading professionals at the Pro-Am of the Weetabix Women's British Open at Royal Lytham & St Anne's next year.