R2 LEADERBOARD US unless stated -6 P Mickelson, S Maruyama (Jpn) -5 J Maggert -4 F Funk, R Goosen -3 A Cabrera (Arg), E Els (SA) -2 V Singh (Fij), C Pavin Selected others: Level S Garcia (Spa) +1 T Woods +3 P Price (Wal) +4 P Harrington (Ire) Clubhouse scores Second round photos

The popular American, who turned 34 on Wednesday, carded four birdies to take his 36-hole score to six under par.

Japan's Shigeki Maruyama had a chance to go one better but bogeyed the last to draw level with Mickelson.

One shot further back is Jeff Maggert, while Fred Funk and Retief Goosen are tied on four under. Tiger Woods is seven shots off the lead at one over.

Mickelson, who won his first major at his 47th attempt, is trying to become only the sixth player to win a Masters-US Open double.

The world number five missed a 10ft birdie putt at the last to break the US Open record of 133 for 36 holes.

He said: "I think you perform the way you prepare and I feel my preparation has been much better going into Augusta and Shinnecock.

It's been a good start - I've been keeping the ball in play well Phil Mickelson More US Open reaction

"I was able to keep it in play and be very aggressive with my approach shots.

"I'm swinging with confidence, knowing where the ball is going and taking half the trouble out of play. All of that makes the course a lot easier."

Should Mickelson triumph, he would join Craig Wood, in 1941, Ben Hogan, in 1951 and 1953, Arnold Palmer, in 1960, Jack Nicklaus, in 1972, and Tiger Woods, in 2002, as the only players to have won the first two majors of the year.

Continually smiling at the huge galleries, he picked up shots at the first, eighth, 12th and 16th on a second successive day of calm weather at Shinnecock Hills.

Mickelson's bogey-free 66 was matched by the veteran Funk, who birdied the last two holes to reach four under, a score also reached by 2001 champion Retief Goosen.

Goosen's South African compatriot Ernie Els is ominously placed on three under, alongside the big-hitting Argentine Angel Cabrera.

Corey Pavin, the winner the last time the US Open was played here in 1995, added a 71 to his opening 67 and stands just four shots off the lead with world number three Vijay Singh.

"I didn't think I would win," the 44-year-old American said. "I just wanted to come in and play the best I can with absolutely no expectations."