Chun In-gee set the lowest winning total in major championship history by finishing the Evian Championship on an incredible 21 under.
The world number seven from South Korea is only the second player in LPGA Tour history to win her first two majors after claiming victory by four shots from compatriots Ryu So-yeon and Park Sung-hyun on Sunday.
Chun finished with a two-under 69 in Evian-les-Bains to add to the U.S. Women's Open she claimed as a non-member last year and better the previous record of 19 under for a woman and 20 under for men in majors.
The 22-year-old started the day with a four-shot advantage and never looked like letting it slip, stretching her advantage to six strokes with five holes to play.
Chun dropped only one shot in her final round, with Ryu and Park signing for 66 and 69 respectively.
"I feel like I'm dreaming now," Chun said.
"Without nerves, I feel bored. Nothing, bored. I had a lot of pressure on the course, but I enjoyed my game. I tried my best to keep to my game plan."