If one hole prevents Phil Mickelson from winning the U.S. Open and moving halfway to a Grand Slam, it will be the magnificent and infamous seventh hole at Shinnecock Hills, known as the Redan. On Thursday, he bogeyed this diabolical hole, which sits like a tilted and cocked table, sloping steeply and slickly from front right to left back. On Saturday, he fell two shots out of the Open lead, tied with Ernie Els and trailing Retief Goosen, because of a nerve-shredding double bogey at No. 7 that left Mickelson fuming about the fairness of a hole that under certain wind conditions can be nearly impossible.

All week, Mickelson has admitted how difficult and mysterious he finds the nefarious Redan. It's gotten into his head. All the other holes at Shinnecock have combined to cause only three Mickelson bogeys. Yet No. 7 has cost him three shots by itself. Goosen and Els have each played the Redan in even par. Though one of the world's hardest holes, it shouldn't be impossible. Unless Mickelson negotiates those 189 yards on Sunday, the Redan may cost him a crown as surely as his butchery of the easy par-5 16th hole (a horrid 6 over par) cost him the 1995 Open when he finished four shots behind Corey Pavin.

"I don't know what to say about that. You saw it. There's nothing else I can add," said a perturbed Mickelson after he missed the green to the left, chipped 10 feet past the hole, then faced a downhill putt so terrifying that he deliberately tried to lag the ball a foot left of the cup so he could survive with a bogey. Yes, one of the greatest putters ever tried to miss a 10-foot putt.

Even so, his putt trickled "30 feet past the hole and I was lucky the ball didn't run all the way off the green." He walked beside his putt, waiting to mark his ball the instant it stopped rolling least a puff of wind blow it farther. The caddie of Shigeki Maruyama actually ran to grab his player's bag, which was sitting by a deep greenside trap, lest Mickelson's putt gain speed and hit the bag for a penalty. Maruyama had already baby-tapped a similar 15-foot putt entirely off the green.

"In general, this is one of the best Open venues I've seen. It's just that one hole," said Mickelson. Is it fair? "You tell me," he said. "Everybody's got to play it."

But everybody didn't have to play it after winds had dried the greens to maximum speed and after those winds had switched to an uncharacteristic direction -- directly behind the putts that Mickelson and Maruyama faced.

By the time they got there "their putts were playing downhill, downwind, down grain, down world," said Walter Driver, the chairman of the USGA Championship Committee. Driver had been so concerned that No. 7 was getting out of hand that he gave instructions that, after Tuesday, all greens except No. 7 were to be rolled twice a day (to make them harder).

Yet, to Driver's disbelief he learned that a groundskeeper had rolled No. 7 with a huge heavy cylinder before Saturday's round. Could we have a Carl Spackler sighting here? What next, groundhogs and dynamite for Sunday at the Open?

"This was not inadvertent. We were not asleep at the switch," Driver said. "Some poor guy rolled it when he shouldn't."

Mickelson and the fourth-place Maruyama, who had a birdie putt turn into a bogey, paid the price.

At 8 a.m. on Sunday, Open officials will meet to decide what to do to prevent having a hole that could turn this national championship into a joke or, more particularly, spook Mickelson, who seems by far the most unnerved of the leaders.

Phil needs help. He needs a strategy if No. 7 is as severe again on Sunday. Perhaps we've found it for him.

If anyone on earth should know how to play a hole called the Redan, a design style first named by a British officer on his return from the Crimean War, it ought to be Prince Andrew, the Duke of York, fourth in line to the British throne and an avid golfer as well as captain of the Royal & Ancient. The prince often materializes at major golf events standing inconspicuously near the leaders. (A disguise helps.) On Saturday, he was practically looking over Mickelson's shoulder at No. 7.

"Does this look like the original Redan at North Berwick" in Scotland, the prince was asked.

"Nothing is the original, is it?" said the prince after the appropriate pause.

Perhaps not, but Shinnecock's Redan is considered the finest illustration of the design anywhere in the world. Charles Blair Macdonald, who rebuilt Shinnecock in 1916 and created the Redan, once wrote about the concept: "Take a narrow table and tilt it a little from right to left, dig a deep bunker on the front side, approach it diagonally, and you have a Redan."

All week, players have tried to analyze how to get a ball to stay anywhere on this green and in a position where two putts are plausible. The hole has lived up to the military derivation of the term -- a Redan fortification on a raised, well-guarded place.

"What do you think the proper line is here?" asked the prince.

My answer is best lost to posterity -- some standard-issue idea about hitting a high left-to-right shot, hold it against the right-to-left wind and let it feed down the green toward the hole. Maybe even bump-and-run the blasted things up the right-front neck.

"I think that Jeff Maggert may have found the proper way," said the prince, nodding at a player in the group on the green. "He hit it into the front bunker, blasted up underneath the hole and made par from there."

Who says the royals don't think outside the box?

Mickelson hit a beautiful looking shot along the conventional lines I'd parroted. The Redan rejected it as distinctly plebeian in conception. The ball bounced down the whole diagonal of the green and off the back.

"Oh, he's gone," said the prince, rendering his verdict, perhaps, on our respective theories.

"I wanted to be down there," said Mickelson of his 8-iron shot. "But I'd just seen Fred Funk [in the previous group] play up from the same place. His ball stopped five feet short of the hole and came right back down the hill at him."

So, fearing a Funky fate, Mickelson played his chip more firmly, ended above the hole, then watched Maruyama putt off the green from the same line. Quite predictably, Phil became discombobulated. Three putts later, he was no longer in the lead.

As Mickelson walked off the green, Prince Andrew turned to a USGA official and said, "Treacherous hole."

At the Masters, Mickelson was able to maintain an almost blissful mood the entire week. Here, he has deliberately tried to continue the same mood management, smiling to the adoring crowds, interacting with the occasional child and refusing to let anything get under his skin. Except, at Augusta National, there is no Redan.

For the rest of his round, Mickelson was slightly off his feed, grinding constantly to save pars and making only one birdie. With two more shots in hand, the whole process would have been so much less stressful. By the last two holes, Mickelson seemed drained and bogeyed both, including a missed four-foot putt at the 18th.

On Sunday, if Mickelson wants to head to the British Open next month with Grand Slam hopes intact, perhaps he should think British. Chin up, don't you know. And, if he wants to take the royal road to victory, aim toward that humble front bunker.

Phil Mickelson anticipates tee shot on par-3, 189-yard No. 7 -- the Redan, where Mickelson is three over after three days: "It's just that one hole." PRINCE ANDREW