Emily Kristine Pedersen of Denmark used a hot start to her second round to post a 5-under 65 and take over the lead at The Annika at Pelican Golf Club in Belleair, Fla.
Pedersen's 12-under 128 broke the tournament 36-hole scoring record by one shot. She was one off the pace to start the day but now sits two strokes ahead of Japan's Minami Katsu, who posted a 67. Thailand's Jasmine Suwannapura shot 65 and moved into third at 9 under.
Pedersen began her round with consecutive birdies to open the back nine. She rolled in three more at Nos. 14, 16 and 18 for a 5-under 30.
She might have moved even further ahead, but each of her three birdies on the front nine was erased by a bogey soon after. A bogey 4 at the par-3 ninth held her at 5 under for the day.
"Holed some good putts. I think the greens were so pure in this morning," Pedersen said. "Not that they weren't this afternoon, but I had a few good rolls to start with.
"Then I think it got a little bit more windy out there and my back nine was not as I hoped. I hit a few uncommitted golf shots that I'm a little bit mad at myself about. I mean, that happens. Hopefully I can commit a bit more tomorrow and keep it going on the whole round."
Pedersen, 27, has won five times on the Ladies European Tour but is searching for her first victory in the United States.
Pedersen is also vying for a spot in next week's season-ending CME Group Tour Championship. The top 60 players in the standings after this tournament will qualify; Pedersen started the week at No 80 but would vault into the top 60 with a win.
"I'm just trying to focus on putting together a good day, a good hole, good shot every day," Pedersen said. "So many times I've looked ahead and it's not gone well, so I'm trying to do something different."
Katsu (No 78 in the Race to the CME Globe) was tied for second with Pedersen at 7-under 63 entering the day. She carded five birdies and two bogeys on Friday.
"I felt like there was a bit of wind today so I was kind of telling myself, wind is going to be my friend for today," Katsu said.
Suwannapura holed eight birdies on Friday to counteract three bogeys, improving on her Thursday score by one. The two-time LPGA winner stood 49th in the CME standings entering the week.
"I think my game has been getting better every week since June," Suwannapura said. "I don't know. I make tons of cuts and it gets more consistently. You know, get more comfortable with my game and I see the positive in my game, and it's just keep playing and have fun with my caddie out there."
World No 4 Jin Young Ko of South Korea had a 69 on Friday and is tied for fourth at 8 under with Lindy Duncan (65), France's Perrine Delacour (65), Wichanee Meechai of Thailand (66), Gaby Lopez of Mexico (67) and Muni He of China (67).
Two-time defending champion Nelly Korda is at 5 under after a 68. Canada's Brooke Henderson, who fired a 62 on Thursday to take the lead, plummeted to 3 under thanks to a 75 that included four bogeys and two double bogeys.
Notables to miss the cut at 1-under par included Stacy Lewis and Celine Boutier of France, both at even par.