Leona Maguire opened with a victory at the Bank of Hope LPGA Match-Play tournament in Las Vegas.
The Cavan native came up against Sweden's Linnea Strom in her first group game and enjoyed a 4&2 win to secure an opening point in her four-player group.
The seventh seed took an early lead, and while Strom levelled the match on the third hole, Maguire took control, going three up over the next four.
Bogey on the par-three eighth hole handed one back to the Swede, but then Maguire increased the lead to four with back-to-back holes secured around the turn.
Strom fought back to win the 11th and 12th, yet Maguire halted the fightback on the 13th to maintain a safe distance in front and secured the 4&2 win on the 16th hole.
Korea duo Na Rin An and Jenny Shin are the other two players in Group 7, and Maguire will face both over Thursday and Friday, ahead of the weekend knock-outs.
The 16 group winners progress to the last 16, and Saturday’s double rounds will determine Sunday’s semi-finalists.
Likewise, Sunday will see the semi-finals played in the morning, following by the championship match later that afternoon.
Top-seeded Lilia Vu cruised to a 4&3 victory over US countrywoman Lauren Hartlage.
Vu, who is ranked fourth in the world, was level with Hartlage through 11 holes before winning each of the next four holes at Shadow Creek Golf Course to seal the win in Group 1.
Vu shrugged off the significance of her seeding.
"I feel like that's pretty circumstantial," she said. "I feel like No. 1 seed for me didn't really matter. ... I have nothing to lose and so does Lauren. I'm just going to go out there and try my best."
Second-seeded Brooke M. Henderson of Canada, the world's eighth-ranked player, posted a 3&2 win over South Korea's Yaeeun Hong in Group 2.
Defending champion Eun-Hee Ji of South Korea opened with a 3-and-2 win over Finland's Matilda Castren in Group 8. The United States' Ally Ewing, who won the event in its first edition two years ago, produced a 3-and-2 victory over Germany's Esther Henseleit.
Other first-day winners included Switzerland's Albane Valenzuela in Group 1, France's Celine Boutier and South Africa's Paula Reto in Group 3, Australia's Karis Davidson and Thailand's Pajaree Anannarukarn in Group 4, China's Muni He in Group 5, Japan's Ayaka Furue and the United States' Stacy Lewis in Group 6 and Ireland's Leona Maguire and South Korea's Jenny Shin in Group 7.
Also posting victories were Ecuador's Daniela Darquea and the United States' Marina Alex in Group 9, the United States' Caroline Inglis and France's Perrine Delacour in Group 10, Sweden's Maja Stark and China's Yu Liu in Group 11, Spain's Carlota Ciganda and Thailand's Pornanong Phatlum in Group 12, Taiwan's Peiyun Chien and the United States' Cheyenne Knight in Group 13, the United States' Angel Yin in Group 14, the United States' Lindsey Weaver-Wright and Sweden's Frida Kinhult in Group 15 and Sweden's Anna Nordqvist and the United States' Lauren Coughlin in Group 16.
