BEDMINSTER, N.J.—Medalists Jordan Spieth of Dallas and Amy Anderson of Oxbow, N.D., have won the USGA boys and girls Junior Amateur Championships.

Spieth posted a 4 and 3 victory over Jay Hwang of San Diego. Anderson defeated Kimberly Kim of Hilo, Hawaii, 6 and 5 in 36-hole matches on the New Course at the Trump National Golf Club today.

It marked the first time since 1991 that the stroke play medalists from the first two days of the tournament have gone on to survive the match play phase.

Tiger Woods beat Brad Zwetschke at Bay Hill in Florida for the boys title that year, his first USGA title. Emilee Klein defeated Kimberly Marshall at Crestview Country Club in Wichita, Kan., for the girls title.

Anderson, 17, was 2 up after the morning round and then won three of the first four holes in the afternoon to take control.

The 15-year-old Spieth, who was one up with eight holes to play in the afternoon round, rolled in birdies at Nos. 11, 13 and 14 holes to take command.