Na Yeon Choi fired a one-under 71 on Friday to stroke lead following the second round of the season-ending CME Group Titleholders.

Choi, who has finished outside the top-three only once in her last four events, had five birdies and two bogeys after an opening double-bogey set her back early at Grand Cypress Resort. Still, she managed to finish 36 holes at seven-under 137, good enough for her seventh such lead on the LPGA Tour.

"I had a very up-and-down day," Choi said. "I have only two more days...focus hard, work hard and do my best and then done (for the season). That's why I think I feel very happy and feel very comfortable."

Choi's converted only two of six such leads into victory, though both came in her last three attempts. Under normal circumstances, her performance in the last couple months would garner more attention, but world No. 1 and Player of the Year Yani Tseng has been the center of attention with her outstanding season.

Still, Choi has a good chance to become the fifth two-time winner on tour this season and would join Tseng (seven wins), Suzann Pettersen, Brittany Lincicome and Karrie Webb.

Sandra Gal, who is also looking for her second win of 2011, shot her second straight three-under 69 and sits alone in second at six-under. Hee Young Park (69) and Paula Creamer (71) share third at four-under 140.

"It was definitely a nice round," Gal said. "Kind of had a slow start, probably got good use of the wind a little bit and I just made some putts on the back nine."

Wendy Ward (71) is fifth at minus-three.

Choi managed to bounce back after a rough start, as a double-bogey at No. 1 followed a bogey to finish Thursday's round. It left her at four-under, but Choi had three birdies in four holes from the seventh to get back to seven- under and atop the leaderboard.

She slowed down from there, but stayed consistent with six pars. Choi finished her round birdie-bogey to remain at seven-under and maintain her one-stroke lead over Gal.

"Today the wind did a lot of switching, so when I choose the club I have to trust the club and just swing hard," Choi said. "It was a very tough day today."

Tough, indeed. Only four players in the 59-player field broke 70 on Friday after 12 did so on Thursday. Gal was one of them, shooting a four-under 32 on the back nine to remain in second for another day.

NOTES: Park, Pettersen and Julieta Granada were the other three to shoot three-under on Friday...Winds averaged 16 m.p.h. Friday, with gusts up to 24 m.p.h...Tseng currently sits in 23rd at two-over-par overall.