PHOENIX, Arizona, March 17, 2013 (AFP) - The 28-year-old American knocked 2012 Founders Cup champion Yani Tseng of Taiwan from atop the rankings after a stay of 109 weeks with the victory and Tseng finishing in a share of 59th place, 19 strokes off the pace.
Lewis became only the second American woman golfer to claim the top spot, after Cristie Kerr in 2010, by making birdies on three of the last four holes while Miyazato, who led most of the way, took a double bogey at the 16th.
"It's unbelievable," Lewis said. "We were battling back and forth, and I didn't expect her to do that there. I was just trying to make birdies there at the end."
World No. 1 "has a pretty good ring to it," Lewis said just one day after taking a two-stroke penalty after her round when her caddie was penalized for testing a bunker.
"It was just fitting with everything that happened yesterday that I had my back against the wall again today," Lewis said.
Lewis, who began the day four off Miyazato's pace after the penalty, fired the best round of the day by two shots to finish on 23-under par 265.
Miyazato, seeking a 10th career LPGA title, settling for second on 268 after a closing 71 at Wildfire Golf Club, where Miyazato set a course record with a 63 in the opening round.
American Angela Stanford was third on 271 with South Korean Jee Young Lee, Italy's Giulia Sergas and Americans Jessica Korda and Lizette Salas sharing fourth another stroke off the pace.
Lewis birdied the par-5 second and fifth holes, the par-4 seventh and ninth as well as the par-5 11th before making her only bogey at the par-4 12th.
She responded with a birdie at the 13th, then ran off three birdies in a row starting at the par-5 15th and ending with a long putt at the par-3 17th to seize a three-stroke lead after the turning point on the par-4 16th.
Miyazato owned a one-stroke lead as she made her approach at 16 with a pitching wedge but the ball rolled off the green and down a hill into the desert and into an unplayable lie.
She blasted the ball up the hill to the far side of an elevated green with her fourth shot and two-putted from there, but the damage was done and Lewis birdied the hole to stretch her advantage to two strokes with two to play.
Leading scores on Sunday after the final round of the $1.5 million LPGA Founders Cup (USA unless noted, par 72):
265 - Stacy Lewis 68-65-68-64
268 - Ai Miyazato (JPN) 63-67-67-71
271 - Angela Stanford 68-70-65-68
272 - Jessica Korda 70-67-69-66, Giulia Sergas (ITA) 69-69-66-68, Lizette Salas 69-68-66-69, Jee Young Lee (KOR) 65-64-72-71
273 - Lindsey Wright (AUS) 68-67-72-66, Candie Kung (TPE) 66-69-71-67, Nicole Castrale 71-67-66-69, Sydnee Michaels 70-67-67-69, Gerina Piller 66-69-68-70
274 - Paula Creamer 69-70-69-66, Jiyai Shin (KOR) 67-70-71-66, Pernilla Lindberg (SWE) 72-66-69-67, I.K. Kim (KOR) 69-67-69-69, Jimin Kang (KOR) 68-69-67-70
275 - Caroline Hedwall (SWE) 70-70-68-67, Mina Harigae 70-68-69-68, Juli Inkster 68-70-69-68-69, Sandra Gal (GER) 67-69-70, Amy Yang (KOR) 68-67-71-69, Karrie Webb (AUS) 70-69-66-70, Thidapa Suwannapura (THA) 69-68-68-70
276 - Jacqui Concolino 70-70-70-66, Austin Ernst 70-72-66-68, Stacy Prammanasudh 69-72-67-68, Inbee Park (KOR) 69-71-64-72