World number two Choi Na-Yeon emerged from a two-and-a-half-hour storm delay to birdie the last hole and dramatically snatch a share of the HSBC Women's Champions lead alongside Stacy Lewis on Saturday.
Choi, who is eyeing the number one ranking of Taiwan's Tseng Yani, holed a 10-footer in front of a big gallery on the damp 18th green to card five-under-par 67 for a total of 14-under 202 at Singapore's par-72 Sentosa Golf Club.
The putt ended an engrossing day-long duel between Choi and America's Lewis, who was incensed when play was halted with the final group already on the 18th fairway and with her narrow one-shot lead in the balance.
When they finally resumed, after a torrential downpour, Choi fired closest to the flag and steadied herself to drain the psychologically important birdie, which left her beaming ahead of Sunday's final round.
"I think that frees me up for tomorrow. I think I can remember that feeling for tomorrow," she said. "I mean, I finished strong and that putt, I hit it pretty solid.
"I was a little nervous for the third shot, I don't know why. A lot of people were waiting, I didn't expect that. But I made it really well and I feel great."
Lewis, the world number four, had remonstrated with officials when play was suspended and bemoaned a "very frustrating" day after she gave up a two-shot overnight lead, finishing with a 69.
"It was very frustrating. We waited all day, the pace of play was not very good, and it's frustrating," she said. "Three fast players are in the back there, and we had to sit there and wait."
Choi and Lewis will play the last round with America's Paula Creamer, who continued to make light of whiplash injuries from a car crash in Thailand last week when she scored 69 to lie two shots back from the leaders.
Thailand's Ariya Jutanugarn, 17, Danielle Kang, Yoo Sun-Young and Azahara Munoz are the closest challengers to the top trio, lying three strokes behind Creamer on nine-under-par 207.
Tseng's 107-week reign as world number one cannot end in Singapore, and it was just as well as the frowning "Pride of Taiwan" bogeyed four out of eight holes around the turn before finishing with 71 for 212, 10 shots off the lead.
Tseng, now into her third year at the top of women's golf, started the season positively with top-three finishes in Australia and Thailand but a poor final position on Sunday will put her number one ranking in serious jeopardy.
Lewis started the day two shots clear, but two bogeys in her first three holes immediately plunged her into a dogfight with Choi, who opened with two birdies to go top.
Lewis hit back with birdies on seven, eight and nine and another on 12 as she twice pulled level with Choi, only for the South Korean to retake the lead with birdies on 10 and 14.
But on the next hole, the par-four 15th, Lewis stormed back into the lead with a snaking birdie putt, while Na left herself too much to do for par and took bogey.
As they teed off on 18, Lewis looked certain to claim the clubhouse lead -- until the siren sounded to halt play, as dark clouds loomed. Creamer, playing one group ahead, finished her round with a sizzling birdie, and in the nick of time.
"My goodness gracious. We saw it (the storm) coming and we're thinking okay, we'll probably all just finish, but honestly I'm shocked that they didn't get the last hole in," she said.
The American, ranked 13th in the world and with nine victories to her name, closed with a precision wedge into the last green which span back within two feet of the hole, earning her a fifth birdie against two bogeys for 69.
"Dinner will taste a lot better," Creamer, who headed straight to the treatment room for work on her whiplash problems, said of her birdie finish.
"Just look forward to a good day tomorrow. This is much more than what I ever expected to be in, this position right now."