Lydia Ko has fired a five-under 67 for her second round at the Women's PGA champs in Maryland.
Ko improved on her first round 71 and now sits tied for second with American Jennifer Kupcho - a remarkable turnaround for the New Zealand golfer; at one point she was 35th yesterday.
Ko came into the tournament after finishing inside the top five in four of her last five LPGA Tour starts. She hasn't had a finish worse than 25th all season.
The two-time major champion described her first round as "a bit of a grind" and was more upbeat about her second round.
"It was nice to have more of those chances - just to feel like I can get on a better momentum and I felt like I did that well today and got lucky when I didn't think it was going to go in and it broke the other way and it went in. So it was that kind of day ... a nice couple of days to go into the weekend."
Overnight leader In Gee Chun, of South Korea, recorded a 69 today, following on from her record-equalling 64 in the first round.
Ko paid tribute to the "unbelievable first round" of Chun and said it gave her some hope that some good rounds can be produced on the difficult course.
"This course is really hard ...I think you have to play strategically and smart and I think I just kept to my game and that's all I can do and hopefully I can do that over the next two days as well."
Ko and Kupcho are six shots adrift of Chun while Caroline Inglis, Sei Young Kim, Jennifer Chang, Brooke Henderson and Caroline Inglis are all on 4 under.
The winner of the Maryland event, the third major of the women's season, will collect $US1.35 million ($NZ2.13m).
-LPGA