Leona Maguire shot up the leaderboard at the T-Mobile Match Play following a three-under-par 69 in Las Vegas.
The Cavan native's second round included six birdies and three bogeys at Shadow Creek to leave her on four under overall, in a share of fifth with Japan's Minami Katsu.
Stephanie Meadow is also well-placed going into the third round as the Jordanstown golfer added a second consecutive level par 72 to sit in a share of ninth.
Meadow hit three birdies and three bogeys through her round and like Maguire, was out among the early starters on Thursday who made hay before the weather break.
First-round leader Sei Young Kim stumbled to 74 but still shares the lead on four under. Spain's Carlota Ciganda shot a bogey-free 67, Angel Yin carded a 68 and Rose Zhang recorded a 73 to move alongside the South Korean.
World number one Nelly Korda is tied for 20th on two over after a 73.
Ciganda, whose two career LPGA wins came back in 2016, said after her round: "I played very solid the last two days. I feel like I've been hitting lots of greens and I think that's key in Shadow Creek.
"If you can hit fairways and greens and avoid those bogeys, those mistakes, I think it's big. And, yeh, my putting was working so I made some good putts, some good saves."
Wednesday and Thursday consisted of stroke play, with a cut to the top 65 players and ties after 36 holes. The field will be cut to the top eight after stroke play on Friday. Saturday morning will begin the single-elimination match-play bracket, with the semi-finals taking place on Saturday afternoon and the championship match contested on Sunday.
Meanwhile, the Australian Women's Classic on the Ladies European Tour has officially been reduced from a 54-hole tournament to a 36-hole tournament due to inclement weather.
Nicole Broch Estrup sits at the top of the leaderboard at Bonville Golf Resort on two under after playing just three holes of her first round.
Lauren Walsh is level par after two holes, with Olivia Mehaffey on one over after a bogey on her opening hole.
