Children wearing "Jack is Back" T-shirts climbed onto tree limbs today to glimpse Jack Nicklaus teeing off beneath them.

Adults waited where they guessed Nicklaus would pass to pat his shoulder and say, "Welcome back."

To scoreboard watchers and casual idolaters at this 80th U.S. Open, Nicklaus' surge to a two-stroke lead -- and a 36-hole Open record of 63-71 -- 134 -- may have seemed a simple and inevitable return to form by the Golden Bear.

What could be more natural than seeing that familiar name atop the list of four mortals who are tied for second place at 136: Lon Hinkle (70 today), Mike Reid (67), Keith Fergus (70) and Isao Aoki (68)?

To find contenders who had ever won a major championship, Nicklaus fanciers at lower Baltusrol had to look past Mark Hayes at 137 to Tom Weiskopf, tied with Pat McGowan at 138, and Tom Watson, who wedged in for an eagle at the 18th, to tie Peter Jacobsen at 139.

If this bear now seems in golden position to become the fourth man to win four Open titles, then it is partly illusion.

Those who followed every Nicklaus step today -- watching the flawed man, not the legend -- saw a proud 40-year-old champion fighting with every reserve of willpower and experience to keep from self-destructing on an ill-starred Friday the 13th full of frustration and near disaster.

Golf is a four-letter word. Both Nicklaus and Weiskopf relearned that lesson today. On Thursday they had played the greatest major-tournament rounds of their careers with a pair of 63s. In the dew this morning, they both came unraveled.

Only Nicklaus could reweave his game, resisting the ugly slide into the pack. By the sixth hole, he led the field by five shots. By the 12th hole -- after two bogies and a double bogey -- he had fallen into a three-way tie for the lead. But, after a birdie and a spectacular save of par on the two closing par 5s, Nicklaus had put himself back on top.

Weiskopf, by contrast, just kept sliding -- shooting 75 to fall four strokes back, finishing bogey, bogey, bogey.

If Thursday was a day of glee as Baltusrol was chewed to pieces, then this was a typically unmerciful Open day of USGA revenge as bizarre stick-the-flag-in-a-bunker pin placements protected the sanctity of par and pushed the cut up to six-over-par 146. Names like Gibby Gilbert, Gary Player, Johnny Miller, Andy Bean and Lee Elder didn't make it.

Only 10 players remained in red under-par figures, and their number is expected to dwindle as this 7,376-yard heirloom bakes. Nonetheless, Nicklaus needs a pair of 70s to break the Open's three-round and four-round records of 205 and 275, respectively, giving him a sweep of the "lap" records in one week.

Of all the tasks in Nicklaus's career, none may prove tougher for him than managing such a steady finish here. His confidence and spirits, seldom higher than they were just a day ago, are teetering once more.

In this round, five of his shots hit the hole and spun or hopped out. He had putts which did 90-degree, 180-degree and 270-degree lip-outs. "I thought one was going to come right back at me," he said. Four other putts "nearly dropped."

Nicklaus spent much of his day scowling at noisy airplanes, muttering "dam" and "Oh God" after lipped putts, and staring disbelievingly at the sky after three consecutive tee shots found brutally unlucky lies.

"I played very well, actually. Very similarly to yesterday," said Nicklaus. "But today all the putts that I made yesterday stayed on the edge. I had some mid-round problems that could have become very serious. But I salvaged the round.

"I'm not going to sneeze at 134 in the Open," said Nicklaus. And then, hiss nose full of summer pollen, Nicklaus could not control himself and sneezed.

"Now honest," he laughed, "I didn't do that on purpose.

What Nickalus knows is that he had a chance to sneeze at the entire field if he could have kept his wheels on. For the first five holes, he was a magnificent animal of attack, knocking down the pin at the 465-yard first and 438-yard third holes for tap-in birdies that put him nine-under-par.

At that juncture, Nicklaus had played a streak of 21 holes in 10 under-par. "I had a chance to leave the field behind," said Nicklaus afterward. "I thought," said partner Aoki, "that Mr. Nicklaus would shoot 65, at that point."

But then an airplane passed overhead as Nicklaus hunched over a three-foot par putt. He backed off. He walked around. He lipped it out. He gave a little curse. The charm was broken.

Golf magic deserts a man a bit at a time. First, it is the birdie putts that won't drop, like the inviting uphill 15- and 10-footers at the eighth and ninth that Nicklaus dearly wanted but couldn't get.

Then, slowly, the metabolism changes. At the 11th, Nicklaus drove dead right into an oblivion of trees and traps. Stymied, he had to chip back to the fairway and take bogey. At the 193-yard 12th, Nicklaus' four-iron shot needed to fly six more inches to clear a trap and bounce at the pin. Instead, it buried itself under the front lip.

A feeble blast, an ugly too-hot chip out of the fringe and a badly missed 10-foot putt later, Nicklaus had his first double bogey of the Open and his wheels were off.

"Don't blow your cool now, Jack," wailed a fan.

But Nicklaus was in a beauty of a blue funk. At the 13th, he tried to hit a high fade and, instead, snap-hooked a drive through a trap into a hideous downhill, sidehill lie that might easily have been unplayable.

"I was starting to feel unlucky," said Nicklaus.

By pure good luck, he had a merciful lie in the rough and gouged an iron onto the green. But he babied a 25-foot putt and left himself a terrifying 10-foot downhill snake for par. His round -- and his entire Open, perhaps -- had reached the crisis point.

"I was disgusted with myself," recalled Nicklaus. "If I hadn't made that putt to save par. I honestly don't know that I might have shot."

Even for Nicklaus, the game is that dicey.

From there to the clubhouse, he never hit a bad shot.

At the 630-yard 17th, he clubbed two woods 580 yards, then flipped a wedge to tap-in a length for a birdie to regain the lead alone.

Finally, at the 18th, bad luck more than bad management conspired to give Nicklaus one last chance to immolate himself. His third shot bounded over the green and under a TV camera.

"I was faced with the sort of little soft flip wedge that I never learned how to hit until this year," said Nicklaus proudly.

Part of Nicklaus' campaign for golf middle age is to master the short game he admits he has neglected all his life. His perfect touch shot at the last hold -- trickling to six inches to save par -- was a testament to several months of remedial work this spring.

It is only a slight exaggeration to say that this Open is approaching the point where its central drama may be the internal battle between Nicklaus and himself.

Three of the four players in second place have more distinguished credentials than most golf fans know.

Aoki has one of the game's most stunning short games. He one-putted every hole on the back nine today, needed only 23 putts for the round and holed 10 par-savers of up to 30 feet. He probably is one of the richest golfers on earth, earning about $500,000 a year in Asian purses and endorsements.

Hinkle, a prodigious hitter, was an anonymous third on the money list last year. Reid simply is the best-kept secret on the tour. "My goal is to get my game to the point where it is totally boring, because that's the way I am . . . quiet and under control," says the slim Reid, tongue only slightly in cheek. "I would like to hit every fairway and green in regulation and never have to do anything exciting."

Despite the excellence of the players on Nicklaus' heels, the man with 17 major championships has one huge advantage on his side which no one else can claim.

"When I stepped to the first tee today," said Nicklaus, "I took out the driver instead of the three-wood. I told myself, 'Be aggressive. You've got a chance to run away and hide from everybody.'"

"Tomorrow when I get to the first tee," said Nicklaus with a small smile, "I'll have exactly the same opportunity again."

The reason he still has that chance is because on a Friday the 13th when he could have cursed his luck and folded, Jack Nicklaus once more decided to determine his own fate.