American Lexi Thompson became the youngest champion in the LPGA's 61-year history, the 16-year-old prodigy firing a two-under par 70 on Sunday to capture the Navistar Classic by five strokes.

Lexi Thompson after her victory at the LPGA Classic in Alabama yesterday.

Thompson, who is seven months and eight days beyond her 16th birthday, finished 72 holes on 17-under par 271 at the $1.3 million event to defeat compatriot Tiffany Joh by five shots and American Angela Stanford by six.

"I knew I was going for the record but I was focussing 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."

American Marlene Hagge won the 18-hole Sarasota Open in 1952 just two weeks past her 18th birthday to become what had been the youngest LPGA champion.