Still almost five months shy of her 17th birthday, Lexi Thompson became the youngest winner in LPGA history, taking the Navistar Classic by five strokes.
Thompson shot a final-round 70 to finish on 17 under to take the £124,000 winner's cheque in Prattville, Alabama.
Marlene Hagge had previously been the youngest champion on tour, winning the Sarasota Open in 1952 aged 18.
"I knew I was going for the record but I was focusing on the golf course and doing my best," Thompson said.
"I was nervous on the first tee but I had a lot of fun out here."
Her father and caddy Scott added: "The feeling is unbelievable. I wanted to cry but I held back. I couldn't be more proud.
"This is the most nerve-wracking thing I have ever done. It's harder on me than her. I just give her the number."
South Africa's Ashleigh Ann Simon, then 18, is the youngest winner on the European tour.
On the men's tour, Italy's Matteo Manassero became the youngest winner on the European Tour when he triumphed at the Castello Masters in Valencia in 2010 aged 17 while in the same year Jason Day won the Byron Nelson Championship aged 19 to take the honours for the PGA tour.