Denmark's Nicole Broch Larsen chipped in for eagle on the 18th hole to share the second round lead at the Ladies Masters at Royal Pines.
Broch Larsen's spectacular finish for a round of 69 tied Swede Camilla Lennarth (68) at 10-under after 36 holes.
They have a two stroke advantage over Canadian Brooke Henderson (71) and Jiyai Shin (70) on Friday.
Broch Larsen opened her round with successive bogeys but showed admirable composure to bounce back strongly.
"To turn a bogey-bogey start to four-under was good," she said.
"I'm quite a long hitter so I had a lot of short-irons to the greens today."
Broch Larsen said she was confident of making eagle or birdie when she stepped onto the 18th tee.
Her five-iron approach on the 423m par-5 missed the green to the right, finishing in a deep swale.
"It was probably the worst place you could be," she said. "But I struck the chip nicely and it hit the pin and dropped."
Lennarth, 27, a laidback Swede, sang Justin Bieber pop songs as she cruised to her 68 which included birdies at three of the final four holes.
"When I first played the back nine here I didn't think the scoring was going to be as low as this," said Lennarth. "I've tried to play smart and have not attacked the pins.
"Today I was a bit shaky with my driver and also my irons. I did not hit it close, but I had a really nice short game."
Broch Larsen said she was exasperated by the slow pace of play which tournament officials must address.
Ladies European Tour official Joao Pinto confirmed numerous players had been spoken to regarding it but no penalties had been imposed. He conceded players taking five hours to complete their rounds was a "bad" situation.
Henderson, the pre-Masters favourite and ranked No.11 in the world, was satisfied with her 71 which included an eagle on the par-5, 12th hole.
"Overall I had a pretty steady day. I would have liked to have done better but two-under is okay," she said.
Henderson uncharacteristically hit three errant drives on the back nine and was punished with two bogeys.
"I managed to save par on the third one," she said.
Well-positioned going into the weekend at three shots off the pace are England's Holly Clyburn and Korean So Young Lee who carded 69s.
England's Felicity Johnson shot a 67 to move to six-under for the tournament but Frenchwoman Marion Ricordeau crashed with a 77 to drop off the leaderboard.
West Australian amateur Hannah Green, 19, continued her recent good form with a 71 to be at four-under but defending champion Su Oh had 74 to be nine shots off the pace.
