Rookie Patty Tavatanakit held off a late charge from Lydia Ko to take the first major of the LPGA season at the ANA Inspiration, while Stephanie Meadow finished in the top 20.
While Northern Ireland's Meadow's final round 67 propelled her up the leaderboard to end on six under in a six-way tie for 19th, Cavan's Leona Maguire who had been within striking distance of the lead after Thursday's opening round, finished up two shots further back on four under after a 70.
But it was Tavatanakit who would emerge victorious.
It was the 21-year-old's first win on the LPGA Tour with a superb 67 on Saturday seeing her enter the final round five shots clear.
An eagle on the par-five second saw her move to 16 under at Rancho Mirage, and two birdies saw her finish on 18 under, two shots clear of Ko.
The New Zealander mounted a late challenge for the title, picking up seven shots on the front nine and three on the way back for a 62, a record low score for a round at the tournament.
Four players were tied for third, seven shots back from Tavatanakit, including Nelly Korda, Sei Young Kim and Nanna Koerstz Madsen.
Inbee Park was among three tied for seventh on 10 under, while England's Mel Reid finished with a 67 and was tied for 14th on seven under alongside compatriot Charley Hull.