Choking is in the eye of the beholder. Popular wisdom will insist that Tom Watson flat-out blew the PGA Championship yesterday, that the nerves so many thought he had overcome in the final rounds of major championships were on the attack again. And that Jerry Pate surely botched that seemingly certain two-putt chance on the 18th hole that allowed John Mahaffey to win a playoff.

That was only partly true.. Nerves were part of the championship, but there was the history of major tournaments coming to the fore once again and also a whole lot of brilliance from Mahaffey, whose life was in disarray two years ago.

No rational person would have bet against Watson as late was the fifth hole yesterday, because he had a six-stroke lead on Pate, Tom Weiskopf and Mahaffey.But anyone with a mind could see that an overwhelming victory for Watson would be a freakish happening.

As Joe Inman had said. "God seems to have an angel on Tom's shoulder." He said that after the third round, because Watson had managed to one-putt 21 times - and sink a trap shot. So Watson was due for an above-par round, if form established over 21 years of strokeplay competition for the PGA title was to hold true.

Nobody wins the PGA without at least one round of even or above par. Gary Player once won with thre above-par rounds and five others had at least two rounds above par. Only Dave Marr, in 1965, Don January, in 1967, and Lanny Wadkins, last year, had even par as their worst performance.

With his putter saving him scads of times, Watson was 10 under after three rounds, seemingly in position to set a record. Putting mortally, with "the angel" off his shoulder, Watson shot a two-over 73.

Less than an hour after Watson ended his third round he was offering sound reasons why he would not fold on the final round. In the lead at a similar point of other majors, Watson would speak confidently but exude an air of tension. Saturday everyone knew Watson now feels at home among golf's elite.

"Hey, who's watchin' a football game?" he yelled, smiling, when he arrived in the press tent and saw a television turned to the Steelers-Colts game. "I'm the star of this show." It was exactly the mood Watson watchers had hoped would one day come, the final step in a progression that began four years ago.

'There's been the pressure to win - and not winning," said Watson's caddy, Bruce Edwards, who has been along nearly every step of the way. "Then he did win and then he overcame that 'choke' stuff and won the British Open and the Masters. Now he knows he can beat these guys if he plays his game.

"He's the best in the world - and I tell him so."

Yet even Edwards is surprised now and then by Watson being Watson, at his extraordinary concentration and obsession with success. After Friday's second round, when he shot 69, Watson spent 90 minutes on the practice tee.

Watson knew the score had been deceptive, that he had made putts of more than 20 feet twice to save par and holed a long bunker shot to avoid bogey. It had been a relatively bad day at the office - and he was working late.

"To give you an idea of his perspective," said Edwards, "he was sent films of those great rounds he had against Nicklaus in the '77 British Open and the Masters. But he's never looked at them. He says, 'There's a time and place for everything and one day it'll be time to look back. But not now'"

In truth, Watson needed only to look sideways to see Mahaffey come on with an Alydar-like rush, to within a shot after 11 holes after trailing by seven before the final round. Mahaffey was scaring the bejabbers out of both Watson and the membership of Oakmont.

After Johnny Miller had embarrassed these scared grounds with that final-round 63 in the final round the U.S. Open five years ago, Oakmont had gone to special pains to make sure that would not happen again.

They had been length and latered the course in other way - and then nature conspired to give players here another chance to deliver a solid blow to this wonderful course. It had rained on and off for most of the first three rounds, as it had before Miller's historic round, and the greens were again "scoring soft."

And Mahaffey went at them in his own quiet fashion, with birds at the 4th, 6th, 8th, 10th and 11th holes. He could have been seven under instead of five under after 11 but two putts within six feet slid by the hole.

This was a rare position for Mahaffey, for the twice had been in the Watson-like leader role and lost two U.S. Open championships, to Lou Graham and Jerry Pate, who also made a charge at Watson in the final round yesterday.

But Pate's was a mere three-under pace after 13 holes, even though it pulled him into a tie with Mahaffey and within a shot of Watson. Mahaffey was going for Oakmont's throat.

Poor Watson was finding himself sinking ever so slowly toward another bad day at the office, though a fine pitch from the rough at No. 17 gave him the bird that allowed him to participate in the first three-way PGA playoff.

For Mahaffey, Miller's record was beyond his grasp. But his winning total, eight under par, was three stokes better than Miller managed in winning the Open here. And the victory brought him to the lofty position he thought he could reach during those Open frustrations.

After those Open defeats, Mahaffey slipped in a hurry. Injuries plagued him. His wife left him. He dropped from eighth on the money list in 1975 to 150th last year, with $9,847 in official money.

All that changed yesterday. Watson would know the feeling.