Scotland's Gemma Dryburgh, who only made the LPGA Match-Play field as a last-minute substitute, advanced to the knockout stage by winning her Friday match and then a tiebreaking playoff in Las Vegas.
Dryburgh (2-1-0) finished tied atop Group 8 with Gaby Lopez (2-1-0) after beating the Mexican 2&1 on Friday at Shadow Creek Golf Course. Dryburgh then captured their head-to-head playoff.
The 64-player field was divided into 16 groups of four in a round-robin group stage that ended Friday. The group winners advance to a 16-player, single-elimination bracket.
Ireland's Stephanie Meadow was eliminated after losing her final group game 2&1 to American Andrea Lee.
Meadow was one up at the turn but Lee was level by the 12th hole and gained further shots on 14 and 17.
"It was amazing to have that (playoff-deciding) putt at the end," Dryburgh said of her win. "(I was) a little bit nervous, but got it in, so it was all good."
"I was disappointed to lose the first match, but I knew I still had a chance to get through. I won yesterday and got it done today. As a reserve at the start of the week, everything was a bit of a bonus, so it's amazing to getinto the knockout stages now."
Top-seeded Minjee Lee (1-2-0) was eliminated by Caroline Masson (3-0-0), with the German advancing out of Group 1 after a 2&1 victory over the Australian.
"It's been a cool three days," Masson said. "Yeah, I think this golf course is really hard, so I feel like I didn't really play my best, but also I think many players probably feel that same way.
"I really made the most of it and just really happy to close it out today."
Others advancing to the round of 16 were Hong Kong's Tiffany Chan (3-0-0) in Group 2, Allisen Corpuz (2-0-1) in Group 3, South Korea's Eun-Hee Ji (2-0-1) in Group 4, Emma Talley (2-0-1) in Group 5, South Korea's Jenny Shin (2-0-1) in Group 6, South Africa's Paula Reto (3-0-0) in Group 7 and Thailand's Moriya Jutanugarn (2-0-1) in Group 9.
Also moving on are Japan's Ayaka Furue (2-0-1) in Group 10, Annie Park (2-0-1) in Group 11, Sweden's Madelene Sagstrom (3-0-0) in Group 12, South Korea's Hye-Jin Choi (3-0-0) in Group 13, Lilia Vu (3-0-0) in Group 14, and England's Jodi Ewart Shadoff (3-0-0) in Group 15.
Jutanugarn had the day's most lopsided victory, 7&5 over Jeongeun Lee6 (0-2-1). Defending champion Ally Ewing (2-1-0) beat South Korea's So Yeon Ryu 1 up but couldn't catch Ewart Shadoff in Group 15.
