Pedersen is on track for a maiden LPGA title at Pelican Golf Club in Florida after pulling clear with birdies on three of the last five holes on Saturday.
She leads at 18 under from South Korea's Amy Yang, who shot a 61, and American two-time major champion Lilia Vu, who posted a 62 to share second spot.
A shot further back are American Alison Lee (62), Thailand's Patty Tavatanakit (62), Spain's Azahara Munoz (64) and Mexican Gaby Lopez (65).
Youngster Steph Kyriacou shot a 64 to be the leading Australian, tied ninth and eight shots behind Pedersen as she battles for a spot in the LPGA finale next week down the Florida coast in Naples.
Only the top 60 in the Race to CME Globe standings qualify for that event and Kyriacou is currently projected to finish 64th after starting this week in 71st.
Grace Kim (69) and Gabriela Ruffels (71) share 50th place in this week's tournament at three under while fellow Aussie Sarah Kemp (73, tied 62nd) is currently projected to scrape into next week at 57th.
Pedersen came to the event in 80th spot on the standings but is now well placed to advance.
Before her third round she spoke with her mental coach, who advised Pedersen to try to lead by more shots at the end of the day than when she started.
"To kind of have something for me to chase, and to just focus on what I was doing and not looking at the others," Pedersen said.
"So that's what I just tried to do. Tried to make more birdies on the weekend than I did the first two days, and that kind of kept me chasing even though I was in the lead.
New Zealand's Lydia Ko, who won the season finale and its $US2 million prize last year, won't be back to defend next week. She is at No. 01 and could only manage a 67, leaving her 11 shots back.
