Lydia Ko shot a stunning eight-under-par 63 to become the youngest ever winner of a major at the Evian Championship.
The New Zealander — at the age of 18 years, four months and 20 days — picked up eight birdies in a flawless final round in France to win by six shots on 16 under par.
American Lexi Thompson was second on 10 under after signing for a 70, with China's Shanshan Feng third on eight under.
Overnight leader Lee Mi-hyang finished in a tie for fourth, with fellow South Korean Lee Ilhee, after a three-over-par 74.
Ireland's Leona Maguire hit her best round of the week, with birdies on the third, sixth, seventh, 11th and 13th leaving her on 68 and in a tie for 34th overall.
American Morgan Pressel, the previous youngest major winner, had been joint third at the start of play but saw her chances end as she made six bogeys in a round of 75, finishing four under.
World number one Inbee Park ended 11 shots off the victory total on five under.
Ko, the world number two, made a steady start to her final round with a birdie at the third and then started to gather momentum after picking up further shots at the seventh and ninth. Five more birdies came on the back nine as she powered to victory.
Thompson had made the early running with four birdies in her first seven holes to move to 13 under, but she could not keep pace with Ko after the turn and a double bogey at the 14th effectively ended her hopes.
Reflecting on her record-breaking achievement, Ko said on Sky Sports: “It is pretty amazing. It was an awesome day. It has been such an unbelievable experience and everybody won’t ask me when I will win my first major because it is done.
“It is probably the best round ever. To finish with two birdies and finish on the last, the 72nd, with a birdie — that doesn’t happen often. It is definitely one of the top rounds of my whole life and I am sure it will be from my career.”
