Morgan Pressel shot 2-under 70 on Saturday and grabbed a 2-stroke lead through the second round of the LPGA Championship.
Pressel, who is seeking her first LPGA Tour win since 2008, finished 36 holes at soggy Locust Hill Country Club at 6-under-par 138.
She will have to endure a marathon Sunday if she wants to secure her second major title, as a rainout on Thursday forced officials to adjust the schedule. Eighteen holes were played both Friday and Saturday and 36 holes are on the docket for Sunday.
"I love this golf course," said Pressel. "I've always enjoyed coming here, coming to Rochester. I stay with a great host family. And I'm just comfortable here, and this golf course certainly plays to my game, and as long as I can keep getting the putts to go in, you know, I think I'll have a good finish."
World No. 1 Inbee Park fired a 4-under 68 on Saturday and jumped into a share of second place at minus-4 with first-round leader Chella Choi, who shot 73. The former won the season's first major, the Kraft Nabisco Championship, in April and will have three of the four legs of the career Grand Slam if she triumphs this week.
"It feels like just one more round to go, but we have to play two rounds in one day," Park said. "I think that's what's going to be very tough mentally and physically. It's something that I really need to handle. And I need to get really good rest tonight. And try to be very relaxed and get a lot of sleep."
World No. 9 Jiyai Shin (73), Amy Yang (70) and Sarah Jane Smith (69) share fourth place at 3-under, while world No. 3 Na Yeon Choi (70), Brittany Lincicome (73), Angela Stanford (71), Catriona Matthew (71) and Sun Young Yoo (69) share seventh at minus-2.
Defending champion Shanshan Feng (70) is tied for 14th at even par, while Stacy Lewis, ranked second in the world, sits a 2-over after rounds of 74 and 72.
Pressel's only major championship victory came at the Kraft Nabisco Championship in 2007, when she became the youngest player in LPGA Tour history to win a major (18 years, 10 months, 9 days). She titled at the Kapalua LPGA Classic in 2008, but hasn't found the winner's circle since. After dealing with a thumb injury throughout 2012, Pressel has just one top-10 finish this season, at the HSBC Women's Champions in February.
Rain continued to fall on Saturday but Pressel wasn't deterred, picking up three birdies over her first six holes after starting from the 10th tee.
"I got off to a good start, had a birdie opportunity on 10, but didn't go in and then made one on 11," she said. "I started to hit my driver a little bit to the right, but made great par saves on 12 and 13, and then two great birdies on 14 and 15 to get me off to a really good and comfortable start."
The strong start was negated when Pressel stumbled to bogeys on Nos. 16 and 18 to make the run at 5-under. She then parred seven straight before dropping her chip within four feet at the par-5 eighth and tapping in for birdie. She parred her last to hit the clubhouse with the lead.
NOTES: Pressel tied for 10th at the HSBC Women's Champions this year ... Park is aiming for her fourth LPGA title of 2013 and third career major championship ... Chella Choi is seeking her first career LPGA Tour win. Her best career finish on the LPGA Tour came at the 2012 Manulife Financial LPGA Classic, where she tied for second after a playoff. She turned pro in 2008 ... Last year, Feng became the first golfer, male or female, from mainland China to win a major championship.