The 115th U.S. Women’s Amateur Championship is down to the final 16 competitors, a group that includes 2015 U.S.  Girls’ Junior champion Eun Jeong Seong, two-time Great Britain & Ireland Curtis Cup competitor Bronte Law, 2014 U.S. Women’s Open qualifier Mathilda Cappeliez and 2014 U.S. Women’s Amateur semifinalist Hannah O’Sullivan.

Here are a couple of Round-of-16 matches to keep an eye on Thursday afternoon with the player’s seeding in parentheses.

Hannah O’Sullivan, Chandler, Ariz. (32) vs. Jennifer Kupcho, Westminster, Colo. (48)

O’Sullivan, 17, will be well rested after needing only 24 holes to eliminate Haley Mills and Justine Dreher by 7-and-6 margins, the latter in the Round of 32 on Thursday morning. The senior at Hamilton High, who plans to attend the University of Southern California in the fall of 2016, is looking to surpass her semifinal performance from a year ago at Nassau Country Club in Glen Cove, N.Y., where she lost to runner-up Brooke Mackenzie Henderson. Currently No. 10 in the Women’s World Amateur Golf Ranking™, O’Sullivan became the youngest winner of a Symetra Tour event earlier this year and advanced to the championship match of the inaugural U.S. Women’s Amateur Four-Ball Championship in May at Bandon Dunes with partner Robynn Ree.  She also tied for 53rd in last month’s U.S. Women’s Open, her second appearance in the major championship.

She faces Kupcho, 18, an incoming freshman at Wake Forest who gutted out a 19-hole win over Haley Moore, O’Sullivan’s Wyndham Cup West teammate and a future USA teammate for next month’s Junior Solheim Cup competition in Germany. Kupcho converted a 15-foot birdie putt on the par-4 first hole to win after Moore, the low amateur in this year’s ANA Inspiration, made a birdie on 18 to extend the match. Kupcho began match play with a 4-and-3 win over Ailea Clark. Two years ago, Kupcho competed in four USGA championships: the U.S. Girls’ Junior, U.S. Women’s Amateur Public Links, U.S. Women’s Amateur; and represented Colorado in the USGA Women’s State Team Championship. This is the second time Kupcho has advanced to the final 16 in a major amateur event this summer, having lost in the Round of 16 at the Women’s Western Amateur. Last year, she won both the Colorado Junior Stroke Play and the Colorado Women’s Match Play championships.

Mathilda Cappeliez, France (28) vs. Elizabeth Wang, San Marino, Calif. (44)

Cappeliez, 17, is the last remaining player of the five who qualified from France. Cappeliez, who finished 59th in last year’s U.S. Women’s Open at Pinehurst No. 2, posted an impressive 4-and-3 win over Kenzie Neisen Thursday morning in the Round of 32. In the Round of 64 on Wednesday, Cappeliez edged Soo Jin Lee, of Australia, 1 up. Cappeliez was a member of France’s winning European Team Championship side this summer. Last year, she missed the match-play cut in the Women’s Amateur at Nassau Country Club.

Wang, 15, has already knocked out a pair of standout collegians. On Wednesday, she beat 2014 USA Curtis Cup competitor Mariah Stackhouse, who led Stanford to the 2015 NCAA Women’s championship in late May, 1 up, and on Thursday morning, she defeated the University of Arizona’s Wanasa Zhou, of Australia, 2 and 1. This is Wang’s third USGA championship appearance, having advanced to the Round of 32 of the U.S. Girls’ Junior two years ago, when she lost to Kathleen Scavo, and falling to Caroline Inglis in the 2013 U.S. Women's Amateur in the Round of 64. Last week, she defeated 2015 Canadian Women’s Amateur champion Mariel Galdiano in a playoff to win the Junior PGA Championship at Miramont Country Club in Bryan, Texas.

Maddie McCrary, Wylie, Texas (31) vs. Sierra Brooks, Sorrento, Fla. (18)

McCrary, a 19-year-old sophomore at Oklahoma State pulled off a big upset in the Round of 64, eliminating 2014 U.S. Women’s Amateur semifinalist Andrea Lee, of Hermosa Beach, Calif., 4 and 3. McCrary continued her strong form in Thursday morning’s Round of 32 with a 3-and-2 decision over fellow Texan Vanessa Ha, of Plano. Ha took out co-medalist Jennifer Hahn in the Round of 64. This is McCrary’s best performance in a USGA championship, having failed to qualify for match play in the 2012 U.S. Girls’ Junior.

Brooks, 17, a senior at Lake Mary Prep, grinded out a tough 1-up win over Hailee Cooper, of Montgomery, Texas, in the Round of 32. She is coming off a strong performance in the American Junior Golf Association’s Wyndham Cup, a Ryder Cup-style competition featuring top male and female players. Representing the East, Brooks halved her singles match with Hannah O’Sullivan. She fell in the Round of 64 at last month’s U.S. Girls’ Junior as well as the 2012 U.S. Women’s Amateur and 2013 U.S. Women’s Amateur Public Links, but USA Today’s 2015 national player of the year is making up for those disappointments this week at Portland Golf Club. Brooks also won the 2015 Women’s Southern Amateur and 2014 South-Atlantic Amateur titles, and was the 2014 Florida state 1A individual champion.  

Bronte Law, England (39) vs. Eun Jeong Seong, Republic of Korea (23)

Nobody has won the U.S. Girls’ Junior and U.S. Women’s Amateur in the same year, but Seong is making a strong bid. After a narrow 1-up Round-of-64 win over 2015 Ladies British Open Amateur champion Celine Boutier, of France, Seong avenged a 3-and-2 loss to Alice Jo in last year’s U.S. Women’s Amateur Public Links final with a solid 5-and-3 win on Thursday morning. JoAnne Gunderson Carner (1956) and Nicole Perrot (2001) have come the closest to pulling off the in-season double. Both lost in the championship match of the U.S. Women’s Amateur after winning the U.S. Girls’ Junior a week earlier. Six players have won both events in their career, the last being Marcy Newton (now Hart) in 2000 at nearby Waverly Country Club. Others to win both titles in their career include Kelli Kuehne, Carner and Pat Hurst.

Her Round-of-16 opponent is no stranger to big matches or big moments. Law, 20, recently defended her English Women’s Amateur title with a 16-stroke victory. She also has competed on a pair of Great Britain & Ireland Curtis Cup Teams, including the 2012 side that ended a seven-Match losing skid to the USA at Nairn Golf Club in Scotland. A junior at UCLA, Law defeated Maddie Szeryk, 3 and 2, in the Round of 64 on Wednesday and then knocked off 2015 NCAA individual runner-up Gaby Lopez, of Mexico, 2 and 1, on Thursday morning.

Lydia Choi, Beverly Hills, Calif. (62) vs. Bethany Wu, Diamond Bar, Calif. (14)

In a couple of weeks, Choi and Wu will be practicing together as members of the UCLA women’s golf team. But on Thursday afternoon, they will be foes for a few hours. Choi, 18, will be a sophomore, while the 18-year-old Wu will be an incoming freshman. Choi survived a 16-for-10 playoff on Wednesday morning before upsetting third-seeded Nelly Korda, 1 up. Korda had set the competitive women’s record on Tuesday with a 6-under 66. Choi continued her momentum on Thursday morning by going all 18 in eliminating Malia Nam, of Kailua, Hawaii.

Wu, meanwhile, is no stranger to USGA championships. Last year, she was the stroke-play medalist in the Women’s Amateur, only to be eliminated in the Round of 64 by Lakareber Abe. Wu was ranked No. 2 in the WAGR when the championship began, but slipped to No. 9 when the new rankings were released on Wednesday. This is already her ninth appearance in a USGA championship and third in the U.S. Women’s Amateur. Last fall, she represented the USA in the Junior Ryder Cup held in Scotland, and she is a three-time American Junior Golf Association All-American (first-team twice).

David Shefter is a senior staff writer for the USGA. Email him at dshefter@usga.org.