Leona Maguire added an excellent round of 67 to her opening 68 and is on nine under par in the Lotte Championship in Hawaii.
The Cavan woman is just two shots off third place, but Yuka Saso of The Philippines shot a marvellous 63 to lead on 16 under par.
Antrim's Stephanie Meadow shot a round of 70, and is seven under par.
Saso, who shared first place after the opening round, carded a second consecutive 8-under-par 64 at Kapolei Golf Club on the island of Oahu.
Her 16-under 128 total has her in front of New Zealand's Lydia Ko, who recorded the best score of the tournament on Friday, a 9-under 63 that leaves her 14 under overall.
Spain's Luna Sobron Galmes (second-round 64), South Korea's Hyo Joo Kim (65), South Korea's So Yeon Ryu (68) and Nelly Korda (68) share third place at 11 under.
Brianna Do (66), Ally Ewing (69) and South Korea's A Lim Kim (64) are tied for for seventh place at 10 under.
Six players, including first-round co-leader Brittany Altomare (71) and amateur Rose Zhang (68), are seven strokes behind Saso, tied for 10th.
Scores have been low in Hawaii 🔥
— LPGA (@LPGA) April 16, 2021
Check out some of the top shots from Thursday at the @LPGALOTTE! 👇 pic.twitter.com/hGr5vdnw6m
Saso, 19, is a regular on the LPGA of Japan Tour, but she finished in the top15 at last year's US Women's Open. She is looking for her first victory on the US-based LPGA Tour.
Her scorecard Friday featured nine birdies, including four in a row around the turn, and just one bogey.
"Two more days, I'm trying to get used to it," said Saso, who admitted she was playing this course for the first time this week. "It's like Philippines but colder than Philippines and windier than Philippines. I made some good putts, had good up and downs, my driving was very consistent today."
This is becoming a regular occurrence. @leona_maguire tied 6th in 2nd round of Lotte C'Ship in Hawaii on LPGA Tour after rounds of 68 & 67 five behind Lydia Ko. Leona already 22nd in the Race to CME Globe Order of Merit. @StephMeadow20 going nicely on -5 after 15. pic.twitter.com/yyyuXxSg4l
— Greg Allen (@gregallenRTE) April 15, 2021
Ko, 23, already has 15 LPGA wins, including two majors, but she hasn't been victorious since April 2018. Her bogey-free round Friday included three different streaks of back-to-back birdies.
"I started off well birdieing my first two holes, and then I think I just continuously gave myself opportunities," Ko said. "Especially around a golf course like this, the more times you're putting for birdie or having chances to putt for birdie the better.
Leader by ✌️
— LPGA (@LPGA) April 16, 2021
Watch Yuka Saso's (-16) second round highlights 👇 pic.twitter.com/aDVcFgjtfA
"Especially when the winds come, I think it's a course where some players can go really low, so feel like I was able to do a pretty good job at that, and nice finishing off with a birdie on the last (hole)."
Zhang, who started on the back nine, had a run of three consecutive birdies before making the turn after consecutive bogeys. The 17-year-old from Southern California closed her round by birdieing three of her last four holes.
"Everything was going pretty well in that birdie stretch, then I did kind of falter on 17 and 18," Zhang said.
"It was just like minor mistakes, and then I also pulled it into the water. But I think I lessened the mistakes out here today and just came back on the back nine."
