KUALA LUMPUR, October 12, 2013 (AFP) - The 18-year-old Thompson, who turned professional in 2010, has put herself in a good position to end her title drought as she has not won on the LPGA Tour since her maiden victory at the Navistar LPGA Classic in 2011.
Thompson shot a 66 on Saturday for a three-day total of 17-under 196 to overtake South Korea's Lee Il-Hee, who led on the first two days but shot a 70 today.
The Florida native could have had an even bigger lead going into the final round, but her long putts on the 14th and 18th holes were millimetres too short and she had to be content with pars.
She had a flawless round with birdies on the fourth, sixth, seventh, 10th and 13th holes.
Now ranked 21st in the world, Thompson has enjoyed a good season and besides her brilliant third place at the Evian Championship last month, she also had top-10 finishes at the HSBC Women's Champions in February, Mobile Bay LPGA Classic (May), Marathon Classic (July) and Safeway Classic (August).
Thompson, who trailed by one after Friday's second round, drew level when Lee bogeyed the second hole.
The American then took the outright lead when play resumed after the rain. Thompson and Lee were both on the green, but Lee could only two-putt for a par while Thompson birdied the hole.
It was a lead she never relinquished going into the last day of the $2 million tournament.
"I felt pretty good going into the round. I had a good practice session before my round so I felt confident before (the first tee off)," she said.
"This game is all about momentum. Once you get a few birdies you feel good and try to keep going. I really focus on my game and not my playing partners."
Asked about her plan for tomorrow as she has a good cushion going into Sunday's final round, Thompson said she will have to play smart.
"I will be in the final group and would know how the other players are doing. I will see when to play aggressive or when to play smart, take a two-putt if I have to," she explained.
Lee said missing a three-foot putt on the second hole made a difference, but was happy to birdie the last hole to cut the deficit from four to three strokes.
"I knew it was going to be big for tomorrow. My driver was not good, but I knew it was going to be hard to play well for four days," she said.
Defending champion and world number one Park In-Bee is 14 strokes off the pace after carding her best round of the tournament with a two-under 69.
The Sime Darby LPGA Malaysia is the second of five tournaments in the Asian swing with events in South Korea, Taiwan and Japan to follow.
Leading scores after the third round Saturday in the $2 million Sime Darby LPGA tournament at the Kuala Lumpur Golf and Country Club:
Third round (Par 71)
196: Lexi Thompson (USA) 67-63-66
199: Lee Il-Hee (KOR) 64-65-70
202: Suzann Pettersen (NOR) 67-68-67, Feng Shanshan (CHN) 67-65-70
204: Anna Nordqvist (SWE) 68-71-65, Karine Icher (FRA) 70-66-68
205: Pornanong Phatlum (THA) 71-66-68, Jodi Ewart Shadoff (ENG) 66-70-69, Ryu So-Yeon (KOR) 70-65-70, Kim In-Kyung (KOR) 67-66-72
206: Park Hee-Young (KOR) 69-67-70, Britany Lang (USA) 65-71-70
207: Alison Walshe (USA) 67-71-69, Stacy Lewis (USA) 69-68-70, Caroline Masson (GER) 67-70-70, Gerina Piller (USA) 70-66-71
208: Michelle Wie (USA) 71-66-71, Cristie Kerr (USA) 67-68-73, Amy Yang (KOR) 72-62-74, Paula Creamer (USA) 66-67-75
209: Jenniffer Johnson (USA) 71-70-68, Azahara Munoz (ESP) 72-68-69, Chella Choi (KOR) 72-66-71, Yoo Sun-Young (KOR) 70-68-71, Caroline Hedwall (SWE) 68-69-72, Mamiko Higa (JPN) 68-66-75
210: Park In-Bee (KOR) 70-71-69, Morgan Pressel (USA) 68-72-70, Sandra Gal (GER) 69-70-71