BANGKOK - Lexi Thompson secured a comfortable victory at the Honda LGPA tournament in Thailand on Sunday, a move that will push her past Stacy Lewis to become the top-ranked American female golfer. The 21-year-old, notching up her seventh career win, hardly broke a sweat as she ended the final day with a 4-under par 68 and a total of 268, an unassailable six strokes ahead of runner-up Chun In-Gee from South Korea. Securing a $240,000 cheque, she became not only the first American to win at the Chonburi course but also the youngest winner there, besting Yani Tseng who triumphed in 2011 at the age of 22. Thompson began the tournament with a blistering 8-under par 64 before suffering a par-72 wobble on day two. But she recovered by day three, shooting another magnificent 64.