California: Graeme McDowell emerged as the halfway leader in the U.S. Open while Phil Mickelson briefly tamed a Pebble Beach course on Friday that has tormented the world`s best players for two days.
Northern Ireland`s McDowell sank two monster birdie putts in a round of 68 that saw him break from a tightly packed field to grab the outright lead at three-under-par.
McDowell will head into the final two rounds two strokes ahead of Mickelson, Ernie Els, Ryo Ishikawa and Dustin Johnson, who all made moves but were stalled by a teasing course.
They were also the only five players in the 156-man field to break par for the first two rounds as a host of major champions failed to make the cut at seven-over.
Tiger Woods did survive after adding a one-over 72 to his first day 74, but his long stranglehold atop the world rankings is now under serious threat from Mickelson.
The U.S. Masters champion shot a brilliant 66, the best round of the tournament so far, and was poised to go even lower after making five birdies in the first eight holes before he too fell victim to the deceptively tough Californian layout.
He lost his momentum when he made a bogey at the ninth and while he retrieved a shot at the 10th he was unable to pick up any more shots on the notoriously tough back nine.
"I made a lot of putts, I was very fortunate," said Mickelson, who can overtake Woods for the number one ranking as early as Sunday. "I just got hot with the putter, made some birdies early on and got through the tough holes with pars."
It was partly because of Woods`s runaway 15-shot victory at the 2000 U.S. Open at Pebble Beach that tournament organizers toughened the layout for this year`s championship, tightening fairways, extending the rough and building more strategically placed bunkers to add to the unique natural hazards of the surrounding beaches and cliffs.
Woods did not make a single birdie in his opening round and although he made three on Saturday he still finished the day seven shots behind McDowell. He has never won a major from that far back but he was still talking up his chances.
"I`m right there in the championship. I just need to make a few more birdies, a few more putts on the weekend and I`ll be right there," said Woods.
`LINKS GOLF ON STEROIDS`
McDowell, his confidence soaring after he recently won the Wales Open, made six birdies, including two putts over 20 feet, but spoiled his progress with three bogeys, including one at his last to leave him his best chance yet of winning a major.
"I`d be lying if I hadn`t thought about picking up the trophy Sunday afternoon," said McDowell "I think that`s only natural but I`m trying to be very realistic about it."
The unflappable Els, who won the U.S. Open in 1994 and 1997, put himself in contention for a third title with a 68 on a course that tested his body and mind but also helped arouse his deepest competitive instincts.
"It`s almost links golf on steroids, with the rough and the grass around the bunkers," the South African said. "I needed a round like today to get me back in the tournament."
Japanese teenager Ishikawa provided another demonstration of why he is regarded as one of the hottest talents in golf with two late birdies in a round of 71.
Playing in his first U.S. Open and being followed by a huge Japanese media contingent still buzzing about his 58 in May, he was given the royal seal of approval from his 60-year-old playing partner Tom Watson.
"He reminded me of me when I was 18," said Watson, who won eight majors, including the 1982 U.S. Open at Pebble Beach.
Johnson is one of the biggest hitters on the tour and his appearance on the leaderboard was no real surprise as he won the last two regular PGA Tour events at Pebble Beach.
The three overnight leaders all dropped back through the field after starting the day at two-under.
Britain`s Paul Casey and Zimbabwe`s Brendon de Jonge shot rounds of 73 to be level par while American Shaun Micheel fell to three-over with a 76. Germany`s Alex Cejka and American Jerry Kelly joined Casey and de Jonge at even par.
Conditions were almost perfect when the early groups teed off with the greens slowed down by overnight watering and only a gentle breeze blowing in from the Pacific Ocean. They were more difficult in the afternoon when Mickelson played, adding more credence to his performance.
But none of the players could really take advantage and were at times made to look like weekend hackers, with at least three players forced to climb off the fairways to play shots from the sides of the cliff and the beach below.
Former U.S. Open champions Geoff Ogilvy and Michael Campbell missed the cut after struggling in both rounds while South Korea`s U.S. PGA champion Yang Yong-eun spectacularly fell apart on the back nine to make an inglorious early exit.
Playing in the same group as Mickelson, he was cruising along after a flawless front nine when he suddenly dropped 13 shots over the back nine, including two triple bogeys and a double.