Naomi Ko is one of eight quarterfinalists (USGA photo)

“It was a big confidence booster,” said Ko about her victory over Khang. “Someone actually asked me if I felt like an underdog going into the match, and I kind of did, but I knew I had a chance because anything can happen in match play.”

Playing in her second Girls’ Junior and first since she missed the cut in 2012, Ko is the 2014 British Columbia Junior Girls’ Amateur champion and will play for North Carolina State University in the fall.

Khang, 17, of Rockland, Mass., was gracious in defeat. “Naomi was awesome, especially on the putting surface,” she said. “She made every birdie putt whenever she was on the green inside 20 feet. She’s a good player, and she’s played well this week.”

Ko’s quarterfinal opponent is 15-year-old Eun Jeong Seong, who she met for the first time Thursday in the clubhouse during a weather delay that pushed the start of play to 9:30 a.m. CDT. Seong, of the Republic of Korea, defeated Aubree Jones and Chakansim Khamborn, both by 6-and-5 margins.

Never losing command in either match, Seong sank six birdies against Jones and five against Khamborn, with the usual match-play concessions. In 2014, Seong was the runner-up and stroke-play medalist at the U.S. Women’s Amateur Public Links at The Home Course in DuPont, Wash. She shot a record-setting 8-under 64 during the second round en route to another championship record for her two-round total of 10-under 134. She credits her success in this year’s Girls’ Junior to that experience, noting patience as her main focus.

Joining Ko and Seong in the quarterfinals are Annika Cedo, of the Philippines; Jayna Choi, of Collierville, Tenn.; Evelyn Arguelles, of Mexico; Mika Liu, of Beverly Hills, Calif.; Angel Yin, of Arcadia, Calif.; and Andrea Lee, of Hermosa Beach, Calif.

Mika Liu, the 2015 U.S. Women’s Amateur Four-Ball champion, utilized her trademark putting skills in defeating Kelly Sim, 3 and 2, and Aneka Seumanutafa, 2 and 1, Thursday. She never trailed in either match.

“I’m just grateful I’ve been able to get this far,” said Liu of making it through the ups and downs of Thursday’s matches.

Liu, an IMG Academy student who has verbally committed to play for Stanford University, will next face 17-year-old Arguelles, who won, 1 up, over Kathleen Scavo in the Round of 16. Of the five players from Mexico in the field, Arguelles is the lone competitor to reach the quarterfinals.

Lee, also committed to Stanford for 2016, arrived in Tulsa less than two hours before her Monday tee time from a silver medal-winning performance at the Pan American Games in Toronto, Ontario, Canada. Lee, 16, has notched the quickest victories of the championship, needing just 37 holes over three matches. After defeating Brooke Seay, 8 and 7, in the Round of 64, she eliminated Sabrina Iqbal, 6 and 4, and her Mira Costa High School classmate Marni Murez, 7 and 6, on Thursday.

"I’ve been hitting fairways, hitting greens, making the putts I need to make and saving pars,” said Lee, who is playing in her third Girls’ Junior. “If I can continue to play the way I’ve been playing – just solid golf – I'll be happy."

In Friday’s quarterfinals, Lee will face fellow three-time Girls’ Junior competitor Yin, who defeated Mexico’s Maria Balcazar, 4 and 3, and Korean-born Yujeong Son, who now resides in Norman, Okla., 5 and 3. Yin, 16, earned medalist honors at the 2014 Girls’ Junior in Flagstaff, Ariz., where her 36-hole stroke-play score of 13-under 131 was the second-lowest 36-hole score in Girls’ Junior and USGA championship history.

Choi’s Round-of-16 battle against Karah Sanford looked like it was headed for extra holes after Sanford pulled all square with a birdie on No. 16. However, the 14-year-old Choi answered with birdies on Nos. 17 and 18 to secure a 2-up win. Choi will face the 16-year-old Cedo, who outlasted Muni He in 21 holes before securing a 4-and-3 victory against Gina Kim.

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