KUALA LUMPUR, 12 Oct, 2014 (AFP) - Feng, 25, notched a three-stroke win over the Thai, who cooled down the stretch just as Feng was heating up, giving the 2012 LPGA Championship winner her fourth Tour win.
Feng punctuated her strong finish with an eagle on the par-five 16th hole at the Kuala Lumpur Golf and Country Club, eventually finishing the tournament at 18-under 266 and taking home the $300,000 first prize.
Pornanong began the day with a three-shot lead over the nearest competitor after the first three rounds on the par-71 course.
But the 24-year-old Thai could manage only a one-under-par 70 on the decisive day, sealing her fate with a double bogey on the par-three 15th hole. She finished at 15-under for the tournament.
Feng, who finished second last year in Malaysia behind America's Lexi Thompson, was four shots behind Pornanong when the day began -- just where she likes to be.
"I think that's what I actually do very often. Like, when I win, I'm usually not leading after the first and second round. I like to come from behind. I had no pressure at all today," she said.
Feng said her disappointing performance in last week's Reignwood LPGA Classic in Beijing, where she was the defending champ and local favourite yet finished tied for 49th, also helped lower the expectations and pressure.
"What I was doing was just to focus on every shot and just try to do my best and hope that putts can fall. That's all I did," she said.
Sweden's Pernilla Lindberg also closed strongly, posting a nine-birdie 63 to finish the week at 14-under and in a tie for third with South Koreans Chella Choi and Ryu So-Yeon.
Korea's Choi Na-Yeon was at 13-under, with compatriot Lee Il-Hee a stroke further back.
World number one Stacy Lewis of the United States, who led after the first round, shot a 69 Sunday, not enough to make up for middle rounds of 71 and 72 on a course that yielded low scores to others.
Lewis finished at seven-under for the $2 million tournament, which is part of the LPGA's annual multi-event swing through Asia.
Final scores on Sunday in the Sime Darby LPGA Malaysia tournament:
266 - Feng Shanshan (CHN) 67-67-69-63
269 - Pornanong Phatlum (THA) 67-67-65-70
270 - Pernilla Lindberg (SWE) 70-68-69-63, Chella Choi (KOR) 69-66-68-67, Ryu So-Yeon (KOR) 66-65-72-67
271 - Choi Na-Yeon (KOR) 66-70-68-67
272 - Lee Il-Hee (KOR) 70-66-68-68
273 - Caroline Masson (GER) 72-67-66-68, Yoo Sun-Young (KOR) 70-67-68-68, Lee Mi-Hyang (KOR) 67-69-69-68, Lydia Ko (NZL) 69-64-70-70
274 - Beatriz Recari (ESP) 70-67-71-66, Brittany Lang (USA) 69-68-71-66, Carlota Ciganda (ESP) 68-69-71-66, Lee Mi-Rim (KOR) 71-67-67-69