Five consecutive birdies brought Tseng to a 12-under par total.
REUNION, Fla. -- Lorena Ochoa will have to come from behind to win a fourth consecutive tournament.
Ochoa shot a 5-under 67 in the second round of the Ginn Open on Friday, leaving her three strokes behind leader Yani Tseng.
Tseng moved to 12 under with a course-record 64. Suzann Pettersen (66) was 10 under, one shot ahead of Ochoa and Minea Blomqvist (66).
"I like coming from behind," Ochoa said. "I don't think you have the pressure to be on top for four days. I really like where I am right now. I feel comfortable where I am. It's nice to be a few shots behind."
Ochoa missed every birdie putt she had during the first eight holes, but got things going on the par-5 ninth. She just missed the green with her second shot, chipped to 6 feet and then sank the putt.
She followed with four more on the back nine, including an up-and-down from a green-side bunker at No. 10 and a 20-footer from the fringe on the 13th.
She needed every one of them to stay close to Tseng, a rookie from Taiwan who earned her card in qualifying school last year.
Tseng's best round on the LPGA Tour was one stroke better than Cristie Kerr's opening round at the Ginn in 2006. It also was three shots shy of her career low round, a 62 she shot as a junior in Indonesia. She ended that round with an eagle.
She finished with a disappointing bogey Friday.
Knowing a 62 was within reach, Tseng said she was "trying too hard the last three holes." It really cost her on No. 18, when she pushed her tee shot into a bunker, had to lay up from there, then played a safe shot to the green that ended up 17 feet from the pin. She just missed the long par putt.
Nonetheless, Tseng was ecstatic with her round that included five consecutive birdies and seven putts of 10 feet or longer.
"It was awesome," she said. "I feel I have a lot of confidence for my putting."
Her entire game has been pretty solid this year. She ranks fifth in scoring average and has five top-25 finishes in as many starts.
She was second at the MasterCard Classic last month, 14th at the Safeway International and tied for 21st at the Kraft Nabisco Championship.
Pettersen checked out the leaderboard at one point, saw Tseng at 13 under and thought, "What course is she playing?"
"I was a little surprised when I saw that number," Pettersen said.
Tseng had hoped to start the third round in the final group with Ochoa. But Pettersen birdied her final hole -- she just missed an eagle putt -- and knocked Ochoa out of the closing threesome.
Now, Tseng will have to settle for watching Ochoa from afar. But given Ochoa's recent run, Tseng might get a pretty good show.
The world's No. 1 player has won four of five starts this year -- by a combined 34 shots -- and has three straight victories. Two of those wins came after the 26-year-old Mexican trailed early. She overcame a three-shot deficit at the Safeway and was down a stroke after the opening round at the Kraft.
"Even when I'm winning, I try to think that I'm behind and try to play my own game and make a lot of birdies," Ochoa said. "That's the only way to keep good focus and play good."
And playing from behind won't cause her to alter her easygoing demeanor.
"I always want to take everybody down," she said. "I think you can do it with a smile on your face and be nice and talking to them. You don't have to be mean or rude."
Annika Sorenstam (73) was 1 under, 11 shots off the lead. Both former Ginn champions, Mi Hyun Kim (2006) and Brittany Lincicome (2007), missed the cut. Kim was 2 over, and Lincicome 6 over. ... Other notables who missed the cut: Laura Diaz, Kelli Kuehne and Se Ri Pak. ... Tseng got some help with her short game this week, borrowing a putter from her coach, two-time PGA champion Dave Stockton. "I don't want to return it to him," she said.