South Korea's Eun-Hee Ji shot a three-under 69 to grab a one-stroke lead over Aussie Karrie Webb after the third round of the LPGA Championship, the second major of the 2012 season.
"Today my iron shots helped with my play. I keep it on the fairway, and I'm hitting really close to the hole and I made the easier putts," Ji said.
On a day when a rain delay halted play for more than two hours, Ji moved to four-under-par 212 at the Locust Hill Country Club course.
Ji won the 2009 US Women's Open, so the 26-year-old is gunning for her second major championship.
Webb had a four-under 68 Saturday, matching Ji for the best round of the tournament.
"Whether I win tomorrow or not, just the feelings that I will have tomorrow with a chance to win is what I work hard for," Webb said.
"And I probably want it more now than I ever have in my career just because I don't feel it as often as I would like."
Ji had a bogey at the fourth which put her at minus-one, but she followed up with consecutive birdies.
On the back nine, Ji birdied 11 and 15 to compile a two-stroke lead, but a bogey at 16 brought her back. She parred the last two holes to maintain her lead.
Ji previously won at Locust Hill in 2008 at the Wegmans, an event that was canceled in 2009 and replaced by the LPGA Championship.
Now Ji is chasing another title on the same course.
Giulia Sergas moved back near the top of the leaderboard with four birdies on the front nine and finished with a 69. Sergas shared the first-round lead before shooting a 76 on Friday.
Sergas was tied at two under with Stacy Lewis, Suzann Pettersen and Inbee Park. Lewis had a 70, Pettersen shot a 71, and Park had a 72. Lewis has won twice in her last three starts.
Paula Creamer stumbled on the back nine and finished with a 73. She was in a seven-way tie at one under.
Defending champion Yani Tseng had her best round of the week, finishing with at 74 after an earlier 76 and 75.
Webb said she expects the leaderboard to get extremely crowded on Sunday.
"It's not just the people in the lead that have a chance to win," she said.
"I think my patience level has really been quite good - for me."
On Thursday "I started feeling sorry for myself. The fact that I overcame that early trouble really reinforced that. The stakes will be a lot higher (Sunday), but I've done a good job so far."
The beginning of the round was delayed for 2.5 hours because of forecasts of rain.