Sweden's Sophie Gustafson fired a three-under 69 to maintain her slim lead after Friday's second round of the LPGA's CVS Challenge.

Gustafson moved to 10-under 134 total for a one-stroke lead over China's Feng Shanshan, Sweden's Maria Hjorth and world number one Lorena Ochoa of Mexico.

"I'm playing good so that obviously helps a lot," Gustafson said. "The irons and driving, but the putting is not good."

Gustafson is seeking her first win since the 2003 Samsung World Championship. She has runner-up finishes in each of the past five years but no victories.

Starting the day with a two-shot lead, Gustafson seized sole possession of the lead Friday on par-four No. 17. She reached the green off the tee then two putted for a birdie.

Gustafson says she is surprised to be leading the tournament despite some poor putting.

"I'm playing good so that obviously helps a lot." she said. "The irons and driving, but the putting is not good."

Feng rolled in six birdies, including on holes No. 17 and 18, en route to a five under 67.

Feng said she didn't settle into her round after a bogey on the 12th hole.

"At the beginning of the day, I was a little bit nervous, because I have not played that well on the first day in a long time," Feng said.

"I was just a little bit nervous so I missed a little par putt on the 12th hole. After I missed that par putt I just relaxed and tried to make some birdie putts. So, it ends up good."

Feng said the setup at the Blackhawk Country Club course suits her style of play.

"I know the course pretty well," Feng said. "I think we are not playing too long this time, and I'm kind of like a long player.

"So, on all of the par-5s, I have chances of getting it on the green in two. So, it's easy to make birdies or eagles."

Ochoa equalled that score while Hjorth carded a 66. Ochoa's round featured an eagle on the par-five No. 11 which she followed with a birdie on the 12th.

Ochoa has clung to her No. 1 ranking despite going winless in her last 10 starts. The Mexican star who has dominated the women's game over the past four seasons.

Her lone bogey came on the par-four first hole after hitting her second shot into the rough.

"I think I am giving myself a lot of birdie chances," Ochoa said. "For the weekend, I will keep it exactly the same. Nothing has gone wrong, so there is nothing to change. I'm just trying to keep it simple."

South Koreans Yoo Sun-young and Kim Joo-mi lead a four-way tie at seven-under 137.

The cut line fell at two-over 146 with 79 players moving on to the weekend.

Jiyai Shin, the tour's leading money winner, withdrew from the tournament.