Cavan’s Leona Maguire took the prize for leading amateur as Ariya Jutanugarn became the first Thai to win a major tournament at the Ricoh Women's British Open.
A final round of 75 saw Maguire finish on four under, six shots ahead of the next best amateur in the field, to take the prize.
Jutanugarn, who blew a golden chance to win the first major of the year at the ANA Inspiration in California in April when bogeying the final three holes, carded a final-round level-par 72 to finish 16 under for the tournament and finished three shots ahead of Mo Martin and Mirim Lee.
The 20-year-old led by two shots overnight after a third-round 66, but her maiden triumph looked in doubt when she double-bogeyed the 13th after South Korean playing partner Lee completed a hat-trick of birdies at the 10th, 11th and 12th to reduce a five-shot deficit to one stroke.
American Martin, who parred the last 10 holes, also closed to within two shots of the lead, but Jutanugarn responded with a birdie at the 17th to move two shots clear with one to play and made par at the last to secure the title, while Lee dropped a shot to finish tied for second.
Martin and Lee both finished on 13 under, while American Stacy Lewis finished outright fourth, two shots further back on 11 under.
Jutanugarn, whose family ran on to the 18th fairway in celebration and showed her with water, is among the favourites to follow up by taking gold at the Rio Olympics.
"For me it was hard today," Jutanugarn told BBC Sport.
"I felt a little bit nervous at times. My mother cried at the end. She said thank you, and that made my day. I think this victory is really important for me and Thai golf. I hope I can inspire some players in Thailand."
Scotland's Catriona Matthew carded a one over par final-round 73 after four birdies and five birdies - she bogeyed three of the last six holes - to finish tied for fifth on nine-under with South Korean Ha Na Jang and Australia's Carrie Webb.
"I had a couple of slack shots on the two par threes on the front nine and it was a bit of a struggle from there," Matthew said.
"It was not too bad a day, but I'm disappointed. The greens were definitely firmer today which made it tougher to get close to them.
"It's great fun playing in front of the crowd with the last group. I'm looking forward to playing at the Olympics in Rio. I just need to move up four places."