PINEHURST - Martin Kaymer seized command of the US Open with a sizzling start to Friday's second round at Pinehurst, taking full advantage of receptive greens to pull away from the field. Kaymer, who began on the back nine, rammed in a spectacular 25-foot birdie putt at the 16th and added a four-foot birdie putt at the third to reach nine-under for the tournament, grabbing a seven-stroke lead with six holes to play.

The German was looking to break the record for the largest 36-hole lead at a US Open, the six-stroke edges enjoyed by Tiger Woods on his way to victory at Pebble Beach in 2000 and Rory McIlroy on his way to winning at Congressional three years ago. McIlroy's US Open record-low 36-hole total of 131 from 2011 was also in jeopardy. Only last month, Kaymer captured the Players Championship to snap a three-year win drought that saw him plunge from world number one to outside the top 60, boosting his confidence.

Now the 29-year-old German is staging an impressive display of precision shotmaking capped by clutch putting that could produce his second major title after the 2010 PGA Championship. Overnight rain softened Pinehurst's notorious turtle-backed greens to their slowest and most receptive state in weeks, no one mastering the opportunity like Kaymer.

He opened at the par-5 10th and sank a six-foot birdie putt, followed with a birdie at 13 and dropped a tense 12-foot par putt at 14 after finding a bunker off the tee. Kaymer, ranked 28th, nailed a spectacular 25-foot birdie putt at the 16th to reach eight-under, his 10th one-putt green in 13 holes, and parred twice to reach the midpoint of his round six shots clear of the field.

That was double the lead he enjoyed when the day began after firing a five-under par 65 on Thursday, the lowest US Open round ever fired at Pinehurst. And Kaymer had predicted eight-over par might be the winning score earlier this week when hot and dry weather had Pinehurst lightning fast and formidable. While Kaymer shined, rivals struggled. Only three other players on the course were under par.

Zimbabwe's Brendon de Jonge and American Dustin Johnson shared second on two-under with Northern Ireland's Graeme McDowell and American Kevin Na. American Brooks Koepka and England's Danny Willett were on one-under, as were six others with afternoon starts. Reigning Masters champion Bubba Watson, who struggled to an opening 76, was among those unlikely to make the cut for the weekend to the low 60 and ties.

World number one Adam Scott, last year's Masters champion from Australia, was fighting to make the weekend after opening with a 73.

Reigning British Open champion Phil Mickelson, a six-time US Open runner-up seeking a victory to complete a career grand slam, was on level-par 70 awaiting an afternoon start. Northern Ireland's McIlroy, coming of a breakup with tennis-star fiancee Caroline Wozniacki and a victory at Wentworth last month, opened on 71 and will tee off in the afternoon, as will defending champion Justin Rose of England, who fired a 72 Thursday.