World golf number one Lydia Ko has been pushed back to a tie for 5th at the latest event on the LPGA tour in San Francisco.
The defending champion carded a solid one-under par second-round 71 to be five-under for the tournament, four strokes behind the leader from Japan, Haru Nomura.
Ko's second round started a with three birdies on holes one, two and three at Lake Merced golf club, but the New Zealander gave back two strokes with bogies on the par three 15th and the par four 17th.
Nomaru picked up two strokes to move from 2nd into 1st on day-two as the overnight leader, Korea's So Yeun Ryu carded a disastrous second-round 75.
After setting a tournament course record 63 on day-one at Lake Merced, the Korean bogied four of the first five holes on Saturday (NZT) before carding three birdies and a further two bogies.
But at six under for the tournament and in a three way tie for 2nd, all is not lost for So Yeun.
Ko, meanwhile, said she was trying to ignore talk of a possible "three-peat" of Swinging Skirts titles.
"Obviously there's a lot of say about it, but I just gotta enjoy it."
Ko lamented the inaccuracy of her driving on day-two and acceded the fast and firm greens were not easy to play.
"Just because you're just off the green doesn't mean it's a gimme par or birdie.
"So it was tough when you don't hit the fairways as much as you want to, but I've just got to maybe go to the range you know, try and get this sorted."
Ko's short game continues to impress, however, and when asked how the smaller clubs had become a strength of such a young player, Ko pointed out it was because she's "not one of the long hitters out here."
Ko, who turns 19 on Monday, confessed to listening to music when she practices her short game.
"I think listening to music gets me more engaged and I just have fun."
As to what music she listens to Ko described it as, "something fast that gets me going and gets me energised. Something I can dance to but I'm not dancing in front of everyone."