Five back-nine bogies means Leona Maguire will start the final day of the ANA Inspiration 12 shots off the lead.
The Cavan native endured a difficult third day at the first major of the year, despite making an eagle at the second hole.
The leader - 21-year-old Patty Tavatanakit - holds a five-stroke advantage on 14-under-par.
Having moved to six-under after a three at the par-five second, Maguire had moved right back into contention.
However, while she reached the turn at six-under, a run of five bogies on the back nine saw her sign for a third round of 74, and a three-round total of two-under-par.
Stephanie Meadow enjoyed a better day on Saturday, posting four birdies in a one-under 71.
She's at one-under-par for the tournament.
Elsewhere yesterday, Banbridge native Olivia Mehaffey went close to landing the prestigious Augusta National Women's Amateur.
Holding her place among the leaders on a tight leaderboard over the course of the three days, Mehaffey will rue a difficult run at Amen Corner.
Finishing at three-over-par, she missed out on the play-off by two shots.
— Golf Channel (@GolfChannel) April 3, 2021
Tsubasa Kajitani beat Emilia Kajitani in extra holes to claim the title.
Mehaffey, one of the game's top amateur players, double-bogeyed the notoriously difficult par-three 12th after finding Rae's Creek.
She also posted bogeys at the ninth, tenth and 18th.
On the PGA Tour, meanwhile, Jordan Spieth looks to be hitting form at just the right time.
The week before players descend on Augusta National for the first men's major of the year, former Masters champion Spieth holds the Valero Texas Open lead alongside England's Matt Wallace.
Both players are at 12-under-par.
An encouraging three-under third round of 69 saw Graeme McDowell climb into the top thirty. He's at two-under.
Padraig Harrington - continuing his busy schedule stateside - enters the final round from two over par.
He carded a second successive two-over 74.