Pressel flew out to a 3-up lead in her first six holes but Wie had an answer. Wie won the seventh hole to cut the margin to 2-down but Pressel reclaimed her 3-up edge when she sank a 15-foot birdie putt at No. 9.
Wie struggled with her driver THursday, and it was evidenced on the par-5 11th. She pushed her drive right then took four more strokes to reach the green but Pressel two-putted for par and took a 4-up lead.
Wie stuck with it and birdied 13 and 14 to get back into the match. But Pressel won the 15th when Wie misplayed a shot out of a bunker. Wie needed to win the 16th to extend the match but she hit another drive right and Pressel two-putted for par to reach the quarterfinal round.
'I played very consistent,' said Pressel, who has played in two U.S. Women's Open. 'In the Opens you can't miss fairways and the rough is pretty thick here, too. So you can't miss fairways here, either. I missed one fairway all day, which is what you need to do.
'I really wanted to play her. I wanted to see how I would fare. I think a lot of people wanted to play her, because she doesn't play many junior events.'
'I feel disappointed but I think everything can be viewed in a positive way,' said Wie, who made the cut at this year's U.S. Women's Open. 'I really like this tournament and I'm happy to come back next year.'
Pressel will face Mina Hariage in the quarterfinals after Hariage beat Brittany Lang in 19 holes.
Defending champion and medalist In-Bee Park pounded Whitney Wade 5 and 4 and will take on Hsiao-Ching Lu in the next round after Lu bested Amanda Blumenherst 4 and 3.
Paula Creamer handled Amie Cochran 4 and 3 in the third round and will battle Julieta Granada in the quarterfinals. Granada advanced Thursday with a 1-up win over Catherina Wang, 1-up.
Sukjin-Lee Wuesthoff defeated Jane Park 4 and 2 Wednesday. Wuesthoff will meet Esther Choe Thursday after Choe pummeled Laura Luethke 5 and 3 in the third round.
The U.S. Girls' Junior Championship is one of 13 championships conducted annually by the United States Golf Association, 10 of which are strictly for amateurs. The U.S. Girls' Junior is open to female amateur golfers who have not reached their 18th birthday prior to the end of the championship and have a USGA Handicap Index of 18.4 or better.