Future Stanford golf teammates Jim Lui of Smithtown, N.Y. and Maverick McNealy of Portola Valley both advanced to match play at the U.S. Junior Amateur Championships on Tuesday at Martis Camp Club in Truckee.
Liu, who shared medalist honors with two other players at last year's tournament, earned the title outright as he shot a 36-hole score of 8-under 136 on the 7,740-yard course.
Liu had rounds of 69 and 67 on the par-72 course to become only the third player in the championship's history to twice earn the stroke-play medal, joining Willie Wood and former Stanford All-American Tiger Woods.
Liu fashioned a bogey-free second round, one stroke off the course record.
The U.S. Junior Amateur Championship consists of 36 holes of stroke play followed by six rounds of match play, with the championship scheduled to conclude with a 36-hole final on Saturday.
The U.S. Junior Amateur is one of 13 national championships conducted annually by the United States Golf Association, 10 of which are strictly for amateurs.
Liu, the 2010 U.S. Junior Amateur champion and the runner-up last year, started on the par-5 10th hole where he had to work hard for a three-putt par. But it was smooth sailing starting on the next hole when he struck a 5-iron to 8 feet for the first of five birdies. Liu made consecutive birdies on Nos. 1 and 2, the second when he hit a wedge to 2 feet. He added a two-putt birdie from 20 feet at the par-5 fourth.
"To be medalist is a good honor," said the 17-year-old Liu, who is participating in his fifth Junior Amateur championship. "It's something to be happy about. You take these two rounds, know that you're playing well, and go forward."
McNealy also fired a second round of 3-under 69 and moved up the ladder to qualify for match play. The key hole for McNealy was the short 323-yard par-4 16th, where he drove the green and made a lengthy, curving putt for an eagle.
McNealy, a quarterfinalist at last year's U.S. Junior Amateur, struggled to a 6-over 78 in the first round with a pair of double bogeys. He finished with a two-day total of 147.
Menlo Park's Bradley Knox, who'll be a senior at Sacred Heart Prep this fall, shot a second round of 5-over 77 and missed the cut after a 36-hole score of 154.
At the U.S. Girls' Junior Golf Championships in Fort Wayne, Ind., Gunn High's Jayshree Sarathy of Palo Alto failed to qualify for match play after shooting a 19-over 163 for 36 holes.