Oakmont, Pa. ? Oh, my.

David Oh, a golfer at Southern California with the nickname Dot, pulled off the biggest shocker of the 103rd U.S. Amateur Thursday, a second-round ouster of long-hitting Trip Kuehne that left the exasperated loser sobbing.

Oh did what the far more experienced Kuehne thought no one could do in a tournament Kuehne felt destined to win — beat him with a subpar round at historically difficult Oakmont Country Club.

Oh, whose previous biggest accomplishment was winning the non-PGA Long Beach Open, was on pace to shoot a 1-under 69 at one of the world’s most difficult courses before closing out the match on No. 17 and winning 3 and 1.

Oh kept the momentum going in Thursday afternoon’s third round, beating Matthew Kohn of Longwood, Fla., 6 and 5. Oh now meets Wake Forest star Bill Haas, the son of PGA Tour pro Jay Haas, in today’s quarterfinals.

The 22-year-old Oh bucked a trend by eliminating a veteran on a day that three golfers 35 or over moved on to the field of eight: 50-year-old George Zahringer, 44-year-old Jerry Courville and 35-year-old Pat Carter. Only two years ago, not a single golfer as old as 30 advanced as far.

Zahringer, the Mid-Amateur (25 and over) champion, defeated two golfers whose combined ages don’t equal his: 21-year J.J. Killeen 2 and 1, and 19-year-old Korey Mahoney 4 and 2.

“My wife tells me it’s me out there and a bunch of kids,” Zahringer said.

Kuehne felt the 7,171-yard Oakmont course gave him the best chance to win the championship he has chased since losing to Tiger Woods in the 1994 final. He was so disappointed after losing to Oh, he fell crying into caddie Mike Tyler’s arms.

“I’m so emotional because this tournament means 10 times more to me than it does to anybody else,” Kuehne said. “I felt this was the best chance I had since 1994 to win. I’ve been playing the best golf I’ve ever played. I had every reason to do well. I never looked past anybody.”

Klein tops LPGA field

Kutztown, Pa. — Emilee Klein birdied her last three holes to break a logjam atop the leaderboard and take a two-stroke lead Thursday after the first round of the Wachovia LPGA Classic.

Klein shot a 6-under 66, two strokes ahead of Meg Mallon, Carin Koch, Dawn Coe-Jones, Soo-Yun Kang and Sunny Lee.

“This course sets up great for me,” Klein said. “It’s not that long and I’m not that long. You have to hit it straight and putt well. Those are my strengths.”

The leader, looking for her fourth career title, was at even par after nine holes. Klein then got hot, making birdies on 10, 11 and 13 before finishing with three short birdie putts.

Five tied at Reno-Tahoe

Reno, Nev. — Bob Tway, Kirk Triplett, Paul Stankowski, Steve Pate and Andy Miller had 5-under 67s to share the lead at the Reno-Tahoe Open before a thunderstorm suspended play Thursday.

Luke Donald, J.P. Hayes, Dennis Paulson and Cameron Beckman were a stroke back, but more than half of the field was unable to complete the round at the 7,472-yard Montreux Golf & Country Club.