PINEHURST, N.C. (AP) -- The second round of the U.S. Open at par-70, 7,562-yard Pinehurst No. 2:
LEADING: Martin Kaymer posted the best 36-hole score in the history of the U.S. Open with his second straight 5-under 65.
DEPARTING: Masters champion Bubba Masters led an exodus of top players - including Hunter Mahan, done in by a two-shot penalty for playing the wrong ball - heading home after missing the cut.
WHERE'S PHIL? Slipping. Mickelson, a runner-up at the U.S. Open a record six times, was at 3 over after following his opening even-par 70 with a 73.
AND TIGER? Still home and still recovering from back surgery, missing his second straight major and sixth since turning pro.
KEY STAT: Kaymer is ranked among the top five in every statistical category that matters - fairways hit, greens in regulation, birdies and total putts - except driving distance, where he ranked 13th.
NOTEWORTHY: Kaymer was just the sixth player in U.S. Open history to reach double-digits under par. Rory McIlroy was the only other player to get there before the weekend, at Congressional in 2011.
QUOTEWORTHY: ''If he does it for two more days, then we're all playing for second spot.'' - Adam Scott, who's ranked No. 1 in the world, talking about Kaymer.
KEY PAIRINGS: Phil Mickelson and Webb Simpson (11:56 a.m. EDT); Adam Scott and Jordan Spieth (2:19 p.m.); Chris Kirk and Rory McIlory (2:30); Brendon Todd and Martin Kaymer (3:25 p.m.)
TELEVISION: NBC Sports, noon to 7:30 p.m.