HARRISON, 13 Jun 2015 (AFP) - The South Korean star birdied three of the last four holes at Westchester Country Club, capping her round with back-to-back birdies for a 54-hole total of 14-under 205 in the second major of the 2015 LPGA season.
Park, who is also homing in on the world number one ranking, was two shots clear of overnight leader and fellow Korean Kim Sei-Young, who stumbled to a three-putt bogey at the final hole of a four-under-par 69 for 207.
"It was a great day for me today," Park said. "The ball-striking stayed really solid."
"Today was the best putting day yet," added Park, who needed only 28 putts. "It gives me a lot of confidence going into tomorrow and finishing with a birdie definitely helped."
LPGA Tour rookie Kim had gone to the final hole tied for the lead, but Park's birdie coupled with her own miscue saw Park suddenly in a commanding position going into the final round.
Park posted the best round of the day and matched her best 18-hole performance in the major tournament she won the last two years, when it was known as the LPGA Championship.
On Sunday Park will be vying to join Annika Sorenstam as the only players to win the tournament three years in a row, a feat Sorenstam accomplished in 2003, 2004 and 2005.
Park is also looking to take the number one ranking of New Zealand teenager Lydia Ko, who missed the cut on Friday -- a first in her precocious pro career.
Far from feeling pressure from the possible three-peat, Park said her prior success in the event made her less tense.
"When you're trying to win the second, third time in a row, it just feels like you've done your homework already," Park said.
"So you feel a little bit more relaxed and you kind of know how it feels like and how it's going to play like."
Sunday won't be the first duel of the season between Park and Kim.
In April Kim snatched the Lotte Championship from Park, chipping in on the final hole of regulation to force a playoff and holing out for an eagle on the first playoff hole.
- Kim feeling comfortable -
A two-time winner on the tour this year, the 22-year-old Kim is trying to become the first LPGA rookie to win a major title since Anna Nordqvist won this tournament in 2009.
Last year South Korean Kim Hyo-Joo lifted the Evian Championship trophy in her first major tournament -- but she wasn't yet a member of the tour.
Kim said she didn't mind chasing Park in the final round.
"I feel comfortable," she said. "Tomorrow I will be aggressive and I will do my best to try to win."
Australian Hall-of-Famer Karrie Webb, who started the day in second place, shook off bogeys at her first two holes to card a one-under 72 and head a trio of players on 211.
She was joined by Norwegian veteran Suzann Pettersen and 17-year-old Canadian sensation Brook Henderson, who both shot 71.
American Morgan Pressel was alone in sixth after a 69 for 212.
Leading third-round scores on Saturday in the Women's PGA Championship, the second major of the 2015 LPGA season (USA unless noted, par-73):
205 - Park In-Bee (KOR) 71-68-66
207 - Kim Sei-Young (KOR) 70-68-69
211 - Suzann Pettersen (NOR) 74-66-71, Brooke Henderson (CAN) 67-73-71, Karrie Webb (AUS) 68-71-72
212 - Morgan Pressel 73-70-69
213 - Feng Shanshan (CHN) 73-72-68, Brittany Lincicome 70-74-69, Kim Hyo-Joo (KOR) 70-74-69
214 - Sakura Yokomine (JPN) 74-71-69, Anna Nordqvist (SWE) 71-73-70, Julieta Granada (PAR) 72-71-71, Lexi Thompson 70-72-72, Stacy Lewis 70-71-73
215 - Ryu So-Yeon (KOR) 72-72-71, Cristie Kerr 70-72-73, Gerina Piller 72-70-73
216 - Q Baek (KOR) 74-71-71, Chella Choi (KOR) 70-74-72, Karine Icher (FRA) 69-75-72, Candie Kung (TPE) 70-72-74
217 - Mika Miyazato (JPN) 74-71-72, Catriona Matthew (SCO) 73-72-72, Hsu Wei-Ling (TPE) 74-71-72, Lee Mi-Rim (KOR) 72-72-73, Jane Rah 70-74-73, Charley Hull (ENG) 68-74-75, Jenny Shin (KOR) 66-75-76