Putting issues for Mickelson

Phil Mickelson admitted the "hole looks like a thimble" after putting problems left him well off the pace at the halfway stage of the US Open.

The left-hander carded a 73 on Friday at Pinehurst to leave himsel on three over par, a massive 13 strokes back of runaway leader Martin Kaymer.

Looking to complete his collection of majors by winning an event he has finished second in no less than six times, Mickelson started out his second round with two birdies in his opening three holes.

However, rather than working his way up the leaderboard he instead slipped the other way, a pair of bogeys before the turn being followed by another three dropped shots on the way back in.

"The hole looks like a thimble to me right now," Mickelson said. "I'm having a hard time finding it.

"I feel like I'm playing well enough to win the U.S. Open. Except for putting.

"I felt like I identified what I was struggling with, and I thought it was my eye line had gotten well over the golf ball.

"So as I moved the ball away and put my eyes over the ball instead of over the top, I felt like that's how I putted last year, so I went back to my regular grip.

"Whenever you putt well and you make short ones and you make those five, six-footers and you're running a couple of 20-footers in, the game feels easy.

"You don't put pressure on yourself to hit it close. You can hit more of the middle of the greens. Your ball striking then becomes a lot easier. Your targets are a lot bigger."

Mickelson hasn't given up hope just yet of joining fellow Americans Gene Sarazen, Ben Hogan, Jack Nicklaus and Tiger Woods, as well as South African Gary Player, in completing a career slam.

Yet the 43-year-old acknowledges he needs something special in his third round if he is to get back in contention, meaning his putter will have to get much hotter than it has been for the first two days.

"I'm not overly optimistic," he said. "I'm not going to give up (but) tomorrow I need to shoot six or seven-under to have a realistic chance.

"The three-putt on (the sixth hole) shook me a little bit. After I've three-putted three or four times, I lose my focus on the other stuff and it really affects my ability to concentrate. I'm just not dialed in."

Mickelson will tee off at 11.56 local time on Saturday alongside 2012 champion Webb Simpson.