The screws of the mind game tightened at the U.S. Open today as Jack Nicklaus stumbled back into a tie for the lead with Japan's Isao Aoki after three rounds of gold's most elegant form of torture.

The stage is set for a final Sunday of frayed nerves, and perhaps some tacky gamesmanship, as four others -- including Tom Watson -- are bunched within two shots of Nicklaus and Aoki's record-setting three-day Open total of six-under-par 204.

"I'd love to have made this a very dull tournament, and I had the chance," said Nicklaus, who shot 70, but held a three-shot lead before playing the comparatively easy final six holes of Lower Baltusrol in an undistinguished two over par.

"I had an opportunity to hide from the field, but, instead, I gave back all the lead I had," said an almost-despondent Nicklaus who even three-putted the 18th green from 30 feet for a final hangdog par when he might have held onto an undisputed lead.

Now, thanks to Nicklaus, this 80th Open has no choice, it is going to be a classic no matter which way it swings.

"If I'd played the last six holes two under par, instead of two over, which isn't an unreasonable expectation, I'd have a four-shot lead," said Nicklaus, in a self-flagellating mood. "Now, I'm vulnerable to six or eight players, instead of only being vulnerable to one or two."

Those most delighted by this turn of events are Aoki, who had his third consecutive 68; Lon Hinkle, third at 69 -- 205, and the dangerous trio of Watson (67), Keith Fergus (70) and Mark Hayes (69) at 206. The only only others under par are lethal Lee Trevino and Craig Stadler at 209.

As a perfect final fillip, Nicklaus and Watson, who will be in the last and next-to-last twosomes, are on the brink of a spat.

The Open always is a golfing grail that men seeking it are in danger of wanting overmuch. But seldom have two champions been as hungry for a prize as Nicklaus and Watson are now. Nicklaus wants to join Bobby Jones and Ben Hogan as the only modern players with four Open titles, while Watson is sick to his heart about never willing golf's highest prize.

"If Jack won tomorrow, I think he might retire from golf," said Watson, who salvaged his tournament by birding five of six holes from the eighth through the 13th today. "He's probably thinking about that now. That's why there's probably a lot more pressure on Jack Nicklaus now than there is on Tom Watson."

Watson said this with his best Huck Finn nonchalance, but they were irritating words and blatant games-manship, if high-level golf ever sees such things. "I don't see how Jack could help but think about retiring on such a high note," added Watson.

"I'll let you know about that on Sunday, if I win," said Nicklaus with a glare. "I'll let him [Watson] know, too."

Then, shaking his head, Nicklaus said, "That's a ridiculous thing for him to say. Why would he volunteer that?"

"Was it Watson's place to bring up such a subject at such a time?" Nicklaus was asked.

"That's the first thing that crossed my mind," said Nicklaus. "Particularly when I haven't talked to him about it. It's a very strange subject for him to bring up.

"Obviously, if I win on Sunday, I'd have every intention of trying to win 19 (major tournaments) and 20 and right on. I have no intention of missing out on this kind of (competitive) fun as long as I can be in the thick of it . . .

"Maybe I have more pressure on me," said Nicklaus, "but maybe it will be easier to win because I've done it before."

So maybe it's just as well that Nicklaus and Watson aren't paired in Sunday's final twosome. The ghost of Baltus Roll might have material for too much mischief.

Nicklaus, however, is not above a bit of one-upmanship when it comes to the fellow with whom he will be paired, the enormously rich , 6-foot, 37-year-old putting wizard Aoki.

"Would I be stunned to see Aoki win?" asked Nicklaus, repeating a query. "Gee, that's a hard question. He hasn't won much outside Japan, has he? Really, the World Match Play in England (1978) is the only thing he's won."

What Aoki can do is score. "He's one of the three best players in the world from inside 100 yards." said Watson. "Maybe the best."

"Aoki plays a style with which I am not personally familiar," said a laughing Nicklaus, who has watched the perennial Asian money-winning leader go around in 27, 23 and 31 putts. "His putting stroke is so smooth, so utterly confident that I'd expect lightning to strike if he ever three-putted. We've played together all three days and he hasn't even come close to three-putting."

Billy Casper's total of only 113 putts in the 1959 Open is considered the record. Aoki has a mere 81 so far. "I've been counting," said Nicklaus, adding pointedly, "but he's watched a few of mine go down, too. He's said, 'Nice putt' to me a few times."

How does Aoki pronounce "Nicklaus?"

"He pronounces it 'Jack,'" said Nicklaus.

Amidst all these head games and head cases, Aoki and Hinkle both seem oblivious and almost amusingly detached.

When Aoki is prodded about being matched with a "big name" like Nicklaus, he enlarges his calm, merry eyes and says, "I am big name, too."

"Mr. Aoki is one very fine fellow," said the cheerful, but excitable and hardly pressure-proof Hinkle. "I'd like to have played the last round with him [instead of Watson]. Golf is a game to him. You look at his face and think 'What pressure?' I'd love to be out there with him Sunday having a good time."

But Sunday is unlikely to be a good time for anyone.

Already, many a sign of strain has shown in every game.

Nicklaus came out with a blazing putter today, sinking front-door beauties of 20, 25 and 25 feet for birdies at the fourth, fifth and seventh holes to reach eight under.

"I felt like I was never going to miss another one, but such was not the case," said Nicklaus with asperity. "I felt very relaxed, confident and composed starting the back nine. That was my chance to hide. And I played like it. But I couldn't make a putt."

The frustration of lost opportunity finally told us Nicklau bogeyed the 14th and 15th, failing to get up and down from a bunker on 14, then "almost four-putting the 15th."

Only an hour before, Watson had been nine shots behind and ready to sink so fast he wouldn't leave a slick.

"I was down, but my caddy gave me a good old-fashioned pep talk before the eighth hole," said Watson. "He told me to relax, make some birdies and get back in the tournament.It just started to roll."

After birdies at Nos. 8, 10, 11, 12 and 13, Watson was alive.

For those without the advantage of desperation, this day was harder. Aoki bogeyed the 15th and 16th, before birdiening the final two par 5s. Hinkle looked exhausted and drained on the closing holes. And Hayes needed an eagle putt at the 18th to turn a potential 71 into a 69.

"I've heard about Open pressure all my career," said Hinkle. "I don't know how to explain it except to say that it's different . . . it's definitely different."

That pressure already has claimed many. Tom Weiskopf continued his disintegration today with a 76 to tack onto his bizarre 63-75 progression. Andy Bean, after missing the cut, was asked for an autograph by a child. Instead, Bean insisted that the boy take his miserable putter as a gift.

Only those who think they are lost and forgotten find the gradually hardening greens and distardly pin placements of Lower Baltusrol to their tastes. For instance, Hubert Green, in the second group of tail-enders who teed off this morning, carded eight consecutive 3s from the ninth through the 16th holes on his way to a leisurely 65.

Those like Stadler and Trevino, who knew they must charge, may have the only loose swings at the first tee Sunday. On top of all the usual Open tension builders, at least six players have a decent chance to win a $50,000 bonus price from a gold magazine for breaking the Open record of 275.

Already those near the lead have begun their long night of thinking and dreaming -- figuring up what an Open crown means.

"On Father's Day, I'd like to win the Open for my father who taught me the game," said Watson. "He's told me to take it easy before this Open not get too excited for it. His advice has been working out well."

Yet, even as he talked about relaxing, Watson, who almost never smokes in public, was sucking on a cigarette.

"The final round of the Open," said Nicklaus, "is not so much a test of golf as a test of judgment."