We could not crawl inside Tom Watson's mind to discover why he said what he did 18 feet from the pin on the 71st hole of the U.S. Open today, in grass only a goat could love. Maybe he implied that he was about to wedge himself into immortality just to muster enough courage to pull par magic out of his blue sweater. But he did call a shot for the ages.

"Better make three here," caddie Bruce Edwards had said as they walked toward what seemed bogey doom, the most gut-wrenching way yet for Watson to lose the one major he coveted above all others.

"Gonna make two," Watson said.

Two! Birdie! Sure, Tom. And the Dow'll hit 990 tomorrow afternoon; Democrats will embrace Reagan; Jack Nicklaus will liquidate his empire and open a driving range in Pomona. But this isn't postvictory fantasy we're talking here, a bit of caddie-player hype to ensure what Watson did gets Ruthian accord in golf history.

He called the shot, said he'd plop that wedge out of the weeds and into the cup. We know that because he bragged on himself a few moments after the blessed ball responded to Watson's will. No sooner had it disappeared than Watson was waltzing across the green, waving the wand. Then he turned toward Edwards and gestured: "Told you so."

So it ranks up there with the great shots of golf: Jerry Pate's five-iron in the '76 Open; Sarazen's double eagle; Nicklaus' one-iron that hit the flag on 17 in the '72 Open here. But, truth be known, it wasn't quite impossible.

Which makes it even better. A craftsman was asked to show his highest skill under the greatest pressure. And he did. The luck involved was the golfing gods choosing to knight Watson on this spot, to keep memorable shot on line with its proper destiny, as if to say: "Tom, you've suffered enough in the Open. This one's yours."

If the thousands who lined 17 could imagine a Watson swoon and Nicklaus charging by for his fifth Open, Watson saw something better as he strode past: the ball.

"It was sitting up," Edwards said. "We could see it as we were walking toward it."

Possibly, hackers in the crowd were gloomier than Watson because that shot is the one we'd least want to face under even quarter-nassau tension. Sharp downhill lie in deep grass. Three steps to the green, four more to the flag. We'd stop it in half a mile. Maybe. Or keep it weed-bound.

Pros think differently. Still, it's a shot most of them would gladly let Watson, master of the up-and-down, hit for them. That he pulled this one off was fittingly ironic, for until that point his play had been very unWatson-like.

For instance, weak-driving Watson had hit 13 of 14 possible fairways. But the world's greatest putter had missed an 18-incher for bird at the seventh hole, barely even touching the cup with an atrocious stab. Jerked it, you jerk, he might have said, censoring himself.

Time after time those who tagged along with Watson made such notes as: "very long drive . . . perfect drive . . . 60 yards past Bill Rogers again . . . has anyone ever hit it farther on nine?"

Nope.

"Not consistently," said the nearest available authority on local lore, former U. S. Golf Association president Sandy Tatum. "He's been in about the same position all four days."

Hackers, prepare to be humbled again. On a 467-yard hole, Mr. Watson was pin-high with an eight iron.

"Not too shabby," he said later.

Then he missed a 10-foot birdie putt.

Watson started being Watson a hole later, when he saved par with a 16-foot putt after disappearing from sight down down a steep seaside hill to chase a pushed short-iron shot. This got the crowd excited, Watson now assuming the lead by a shot.

"Gotta want it," one of them shouted.

As though Watson hasn't thirsted for the Open for as long as it started to have unique meaning for him, from childhood.

"My father would say: 'Who won the Open in '33?' And I'd say: 'Johnny Goodman,'" Watson said at the victory ceremony. "He'd say: Who won in '22?' And I'd say: 'Sarazen.' I've been dreaming of this moment since I was 10 years old; this (seventh major) championship means more than any."

He seemed to lose it, then win it and then lose it again so many times: the missed bird at seven, the 35-foot bird at 14, the one dreadful drive of the day, at 16.

In any tournament at Pebble Beach but this one, Watson would have had a chance to hit the green from where he pushed that tee ball: a fairway bunker. For this Open, the trap was deepened and the lip lifted, so any sin from the tee was almost-certain bogey.

His first error off the tee might have made Watson edgy before he struck his two-iron on 17. It seemed so, for Watson pulled that shot after pushing a wood the hole before. But all that did was set up as thrilling a scene as anyone could have imagined.

This day was a feast for even casual golfers: Watson and Nicklaus going at one another on a course that blends beauty and bestiality better than any in America; one of Bing's sons, Nathaniel, being low amateur; one shot to cherish.

"When he walked up the 18th fairway," Edwards recalled, "Tom said: 'This is exactly where I want to be.'

"I said: 'You mean above the hole?'

"He said: 'No, with two putts to win the Open.'"

He used just one.

"His attitude has been better than the last four or five Opens," Edwards said. "I told him it seemed like he was 26 years old. He's always been a fighter. His patience was excellent this week. His routine was deliberate, and that was the key."

This was the Open so many had forecast for Watson for so long, the one on a familiar course that least penalizes the weakest parts of his game. He needed an Open to make his resume for legend close to complete, and a fellow already there--Nicklaus--made him feel at home.

"Don't know about you, Watson," Nicklaus said. "I've seen you do a lot of sensational things. I saw you hit that tee shot at 17, and I was very eager about winning. Then I saw you hit the chip, and I'm sitting here as runnerup. Fabulous."