China's Shanshan Feng retained her Buick Championship title with a play-off victory over South Korean Na Yeon Choi after an exciting final round duel at Shanghai Qizhong Garden Golf Club.
Sharing the lead for the last three rounds, both Choi and Feng carded 67s in testing conditions for a matching 72-hole total of 14-under-par.
Choi led for most of the round until she bogeyed the 18th in regulation play and then again in the play-off.
"I didn't expect it!" said Feng, who made a birdie putt of around 10 feet at the first extra hole.
"Today, from the beginning, Na Yeon was ahead and I was behind, but I never gave up. When we had two holes left I thought, 'I'm just going to try my best and see what happens,' and I think I had luck on my side. I'm really happy to finish with a birdie on the last hole and I'm really proud that I was able to defend my title."
The 26-year-old world number 10, from Guangzhou, pulled a stroke ahead of Choi with the first of three straight birdies at the fourth hole. Both players birdied the fifth and sixth but Feng dropped back into a share of the lead with a bogey on the eighth. Choi then birdied the long ninth gaining a one stroke advantage through the turn.
The 28-year-old world number 18, from Seoul, moved two strokes clear after 11, but Feng birdied 12 before they both birdied 13 and Choi looked totally in control as she chipped in for birdie at the 14th to move two ahead again.
Yet Choi's driving became unreliable down the stretch and she had to take an unplayable drop on 15 after hitting her ball under a tree in long meadow grass. She made an incredible bogey to stay one ahead of Feng and then birdied 16. But after a heavy shower set in and play was suspended for 30 minute due to the threat of lightning, the momentum turned. Feng holed a birdie putt on 17 to get within a stroke of the lead and Choi then found difficulty off the 18th tee.
Feng said: "frustration turned into motivation" and she made her par as Choi took a bogey. In the play-off, Choi's first putt travelled way past the hole and she missed the return, before Feng made her birdie attempt from around 10 feet.
It meant that Feng, the 2015 LET Order of Merit winner, collected her fourth Chinese title, worth 72,966.71 Euro, which was her sixth LET title and 15th victory as a professional.
Last year's ISPS HANDA Ladies European Masters champion, Beth Allen of the United States, finished six shots further back in outright third position to return to the top of the LET Order of Merit. She finished in style by sinking a birdie putt of four feet on the 18th hole: previously her nemesis.
"It was tough unless you got off to a pretty good start, and I just hung in there and did the best I could and I'm happy with third," said Allen, who had played the 18th in four over par for the first three rounds. "I got back with a vengeance and I'm really proud of myself. I've always had issues with that hole, no idea why, but I nailed it."
Becky Morgan from Wales finished in fourth place on seven-under-par, while the 2015 Sanya Ladies Open champion Xiyu Lin shared fifth with England's Georgia Hall, who equalled her career best finish on the LET. China's Wei Wei Zhang was seventh, one stroke ahead of Australian Rebecca Artis and English pair Melissa Reid and Florentyna Parker.
England defeated New Zealand 49-46 to level up the three-match Series at 1-1 heading into the deciding match on Wednesday morning.
Sloane Stephens advanced to her first Grand Slam final at the US Open on Thursday night