American duo Angela Stanford and Katie Futcher were locked in a three-way tie Friday with South Korea's Jenny Shin after the second round of the HSBC Women's Champions tournament in Singapore.
Overnight leader Stanford, who had a two-shot cushion after the first 18 holes, had a two-under 70 for a total of eight-under 136 while Futcher and Shin each posted 67 in the second round.
World number one and pre-tournament favourite Yani Tseng had a disappointing day and lost further ground on the leaders.
The Texan Stanford expects the last two rounds to be even tougher and believes staying patient would be even more important if she is to make it to Sunday.
"I think it gets harder as the tournament goes along to be patient so I am really going to try and stay focused on playing my game and taking advantage of the holes that I feel like I can take advantage of and being okay with par," she said.
"It will be tougher tomorrow and really tough on Sunday but that's the game plan."
Futcher, who was a promising swimmer in her junior days before taking up golf, said making par at the first hole calmed her nerves for the rest of the round.
"Went out, made a great putt on number one today for par, and that kind of really just got me settled and I was able after that to hit it pretty close and make a couple of putts," she said.
Japan's Ai Miyazato, the 2010 champion, was three shots behind the co-leaders after posting a 70 for a total of five-under 139 at the halfway stage of the tournament and tied at fourth spot.
She bogeyed the fifth and seventeenth holes but was otherwise pleased with her second-round performance at the $1.4-million event being staged at the Tanah Merah Country Club's par-72 Garden Course.
"Seventeen was a little bit disappointing but I know I learned something for tomorrow," she said.
"All in all, it went well. I'm very happy."
Tseng had a frustrating outing and is one-under after two rounds for a total of 143 but the Taiwanese superstar refused to blame her sore elbow for her performance.
"It was a little bit sore when I was playing today but it has been much better compared to the last few days," Tseng said of the tendonitis afflicting her right elbow.
"I didn't play that well today, it was more to do with my decisions out there on the course today," she said.
"I didn't give myself a lot of birdie opportunities today and I need to be more confident in my decision making."
Tseng was the pre-tournament favourite heading into Singapore after successfully defending her title at the Honda LPGA Thailand on Sunday and was bidding to win for the first time here.
"I just have to play my game tomorrow and not think too much or worry too much," she said.
There is no halfway-cut for the event which means there is still an opportunity for those lower down the field to work their way into contention for the title.