The opening round of match play in the 2nd U.S. Women’s Amateur Four-Ball Championship at Streamsong Blue was not a good one for the top seeds. Seven of the 10 top sides were eliminated, including the duo of Kristen Gillman and Sierra Brooks, who had never lost a four-ball match until Monday’s 1-down defeat to Nicole and Waverly Whiston. The Nos. 2, 3, 4, 5, 6, 9 and 10 seeds all exited early, once again highlighting the fickle nature of match play.

What will the Round of 16 provide on Tuesday morning? Here are five things to watch:

Sisters Act

Three sister teams qualified for the championship and two remain: the aforementioned Whistons from San Diego, and Yu Chiang Hou, 15, and Yu Sang Hou, 16, of Chinese Taipei.

Nicole, 14, and Waverly, 16, upset the No. 2 seeds on Monday, a side that featured the 2014 U.S. Women’s Amateur champion (Gillman) and the 2015 U.S. Women’s Amateur runner-up and 2016 USA Curtis Cup Team member (Brooks). On Tuesday at 7:49 a.m. EDT, the Whiston sisters face 15-year-olds Sofia Chabon and Mikhaela Fortuna, both of the Philippines. Chabon advanced to the Round of 16 in the 2014 U.S. Girls’ Junior, while Fortuna is competing in her first USGA championship.

Yu Sang qualified for the U.S. Women’s Open prior to arriving in Florida for the Women’s Amateur Four-Ball. Both golfers received invitations to the Swinging Skirts LPGA Classic at Lake Merced Golf Club last month, an event sponsored by a Chinese Taipei foundation. Yu Sang and Yu Chiang each have Swinging Skirts golf bags.

They have a formidable challenge at 7:12 a.m. against 2015 Women’s Amateur Four-Ball semifinalists Madelein Herr, 18, of New Hope, Pa., and Brynn Walker, 17, of St. Davids, Pa. Herr is headed to Penn State in the fall and Walker will play for the University of North Carolina.

California Dreaming

Northern California and Southern California have always had a rivalry and it gets renewed again at 7:36 a.m. when the field’s youngest side, Brianna Navarrosa, 13, of San Diego, and Angelina Kim, 13, of Los Angeles, faces Yonhee Kim, 18, of San Ramon, and Yealini Noh, 14, of Concord. Kim and Navarrosa (No. 12) are the fourth-highest seeded team remaining. Noh and Kim are coming off a 1-up upset of No. 5-seeded Evelyn Arguelles and Isabella Fierro, of Mexico.

Déjà Vu?

Only two mid-amateur teams managed to reach the quarterfinals in last year’s championship, and three of those competitors will play each other for a chance to repeat the feat.

Meghan Stasi, 37, of Fort Lauderdale, Fla., and Dawn Woodard, 41, of Greer, S.C., fell in the final eight to Herr and Walker, while Katie Miller, 31, of Jeannette, Pa., reached the 2015 quarters with partner Amber Marsh Elliott. This year Miller teamed with Kristen Obush, 32, of Greensburg, Pa., and after a 3-and-1 win by Miller-Obush and a 20-hole victory by Stasi-Woodard on Monday, they get a chance to square off at 7:24 a.m. for a quarterfinal spot.

Another Step Forward

Last year at Bandon Dunes Golf Resort, mid-amateurs Olivia Herrick, 27, of Roseville, Minn., and Samantha Sommers, 27, of St. Cloud, Minn., qualified for match play, but failed to advance further. This year, the side rolled to a 6-and-4 victory in the Round of 32 to earn an 8:24 a.m. matchup against No. 11-seeded Brooke Seay, of Rancho Santa Fe, Calif., and Carolyn Zhao, of San Diego, Calif.

Should Herrick and Sommers prevail, they have the possibility of facing another post-college tandem of Alexandra Austin, 23, of Burke, Va., and 2015 U.S. Women’s Mid-Amateur champion Lauren Greenlief, 25, of Oakton, Va.

While mid-amateur sides met in the U.S. Amateur Four-Ball final last year at The Olympic Club, the Women’s Amateur Four-Ball final featured all-junior teams.

Numbers Game

When match play began, Florida was represented by 12 players out of the 64 (32 sides) who qualified from stroke play. That number dwindled to three after the Round of 32, with only one all-Florida side still intact. That would be Latanna Stone, 14, of Riverview, and Hannah Leiner, 17, of Pompano Beach, who eliminated the local favorites, Kendall Griffin, of Winter Haven, and Athena Yang, of Sebring, 1 up. Stasi is the other Floridian still in the draw.

California leads the way with nine players, eight of whom are partnering.

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