Jack may be back, but Hal is here.

The throngs at steamy Riviera Country Club tried to sprain their vocal cords this afternoon imploring Jack Nicklaus to pull off one of the most thrilling and improbable comebacks of his nonpareil career in the PGA championship.

Nicklaus shot a 66 that filled the barrancas and gorges of this lush floral paradise with the familiar, yet still chilling echoes of "Jack's Back," and "Here Comes the Bear." Once again, the man with the greatest game face in sports was stalking his prey, glaring at a golf course as though the very facts of nature--trees and sand--would be unwise to thwart his will.

But, in the end, this was the day for Hal Sutton's arrival as well as Nicklaus' return. Those who saw Sutton's one-stroke victory over Nicklaus--274 to 275--in this 65th PGA will want to sing hosannahs to the 24-year-old hero of the future. After homage has been paid to the Nicklaus legend, they'll get around to giving Sutton his due. And what a due it is.

Today, Sutton, the 1980 U.S. amateur champ, won his first major pro title, and his second major championship overall. His $100,000 first-place check all but assures him of being the 1983 PGA Tour leading money winner ($397,684). This title, along with the rich TPC he won in March, should give him a lock on player of the year honors, too. Last year, Sutton was rookie of the year. It seems like he's in a hurry. The last fellow to start a career this fast was Jack Nicklaus in the early '60s.

Sutton's 65-66-72-71 work here broke the Riv's scoring record of 276, a mark set by Ben Hogan in the 1948 U.S. Open. Sutton also became the first player in the history of the PGA championship to finish at 10 under par (the PGA scoring record of 271 was set on a par-70 course). Until today, Riviera was Hogan's Alley. Now, perhaps it should be called Sutton's Sauna.

Nicklaus must be getting sick of standing by the scorer's tent near the 72nd green to offer his cheeriest congratulations to some wholesome, piercing-eyed young gentleman who has just respectfully but firmly taken a major title away from him. Last summer, it was Tom Watson in the U.S. Open who spoiled what might have been the Olden Bear's greatest hour. Now, it's Sutton who has prevented Nicklaus from collecting his 20th major.

Sutton began the day six shots ahead of Nicklaus, then steadied himself after a bogey-bogey-bogey near collapse at the 12th, 13th and 14th when he plunged into the greenside Kikuyu grass three times. Sutton truly earned his title by closing with four straight pars after he knew Nicklaus had carved his margin to one stroke.

Sutton's coup de grace was a rock-solid par at the legendarily difficult 447-yard 18th hole--an uphill terror on which Nicklaus took his only double bogey of the week, on Thursday. Sutton drove to the center of the fairway, laced a five-iron shot to 14 feet and calmly two-putted.

Peter Jacobsen shot this PGA's low round, a 64, for 276 and third; however, he bogeyed the 18th while Sutton was still on 15 and never was a realistic threat. Pat McGowan (69) was fourth at 277, a shot ahead of John Fought. Ben Crenshaw, who began the day two shots behind Sutton in second place, disgraced himself with a wild-driving Jungle Ben round of 77 that plummeted him to ninth place. Sentimental underdog Buddy Whitten shot 77 for 286 and a tie for 27th place; his $3,200 check may be enough to help get that needle out of his heel.

This day was dominated by the inspired Nicklaus, who had the landscape awash in war whoops of joy, and the square-jawed and clenched-jawed Sutton, who was desperately holding on for the sake of his golfing sanity.

"Yes, this probably was a turning point in my career," said Sutton, whose Sunday 77 two weeks ago blew a six-shot lead in the Anheuser-Busch Classic. "Williamsburg stayed there in my thoughts all day. It became real prevalent in my mind after the third bogey. I said, 'I'm not going to let this happen again' . . . I felt that my thinking was coming apart, not my game. I was going from aggressive to conservative.

"The crowd wasn't the only one who knew the Bear was comin'," quipped Sutton. "I told myself, 'Well, I don't need to do this two weeks in a row on national TV.'

"I certainly felt the challenge. I said, 'This is what it's all about . . . to accept the challenge and come through."

This he did with such elan that Nicklaus greeted Sutton behind the 18th green with the words, "Hal, that will be the first of many for you."

Years from today, if Sutton has his way, we may look back on this day as the occasion when the new bear supplanted the old. From his hair to his glare, from his bulging forearms to his powerful legs, Sutton looks more like a younger Nicklaus than any other player on tour. But there have been potential heirs to Nicklaus and none has ever approached his decade-upon-decade consistency.

Even in defeat today, Nicklaus, 43, reasserted his unique position in the game. He has not only won 19 majors, but now has been runner-up in 16--another whopping all-time record.

"It's kind of fun to come down to the end again," said a grinning Nicklaus, who made no bogeys and had birdies at the second, fifth, 10th, 14th and 16th holes. "I was miserable for about four months (in a midseason slump) . . . Now that I'm playing well, I guess it's over (the '83 majors). That's the way it works, isn't it?"

Both Sutton and Nicklaus came here with something important to prove to themselves. Sutton wanted the world to know he wasn't a choker. Nicklaus wanted to show that his dismal performances in the majors--like a 300 at the U.S. Open--were not the beginning of the end.

"I'm relieved that I relinquished that choking thing that they put on me," said Sutton. "I hate that word. You read it enough, though, and you can begin to believe it . . . I'd gladly reach in my pocket and give you this check back (for $100,000) just to say I'd won this championship."

"My composure, my ability to make putts when I really need them, and my ability to hold an excellent round together are just as good as ever," said Nicklaus. "I'm not as good a player as I used to be."

Sutton had no doubt about how he won. And Nicklaus was equally clear about the reason he lost.

"The second hole (a 460-yard par 4) was good to me all week," said Sutton. "I only hit that green once all week, and I played it one under par." On Saturday, Sutton made what he called the greatest up and down for a par that he'd ever made. Today, he drove so wildly that he almost went out of bounds into the driving range. Hunched under a tree, he couldn't even chip the ball sideways back to the fairway.

Then, from 205 yards away in the rough, Sutton smote a four-iron shot to four-foot tap in range with what he called "a reeeaal critical par."

Nicklaus was equally certain he lost with miserable play on the par-5s here--Nos. 1, 11 and 17. Trying for eagle today at No. 1, Nicklaus found Kikuyu jail with his second shot and settled for par. At the 11th and 17th, he had simple punch shots of 40 and 79 yards that dozens in the gallery could have nudged within 15 feet of the hole--at worst. Nicklaus hit duffer shots on both, leaving the putts 30 and 40 feet short of the hole as the crowd gasped. He settled for par on both and did a slow burn.

This PGA's final hour was one of exceptional drama. After Sutton's third straight bogey, and Nicklaus' 18-foot birdie at the 16th ("read it wrong, hit it wrong, went in the hole"), every soul knew Sutton's lead was one shot.

"My only concern was if Jack birdied the 17th that would put me behind the eight ball. I'd have to make another birdie to win," said Sutton.

When Nicklaus hashed his chance at 17, Sutton's collar loosened. His final putt at 18 was tensionless.

"I've got a high percentage," said Sutton, "from four inches."

Once, the world was full of kings. It was an established occupation. The regal nod. The graceful, genuine smile in response to adulation. The dignified acceptance of the burdens of greatness. The passion for high competition. Richard the Lion Hearted. All those Henrys. Lots of 'em.

Now, to get a hint of that quality of kingliness, we must search in unlikely places. Jack Nicklaus, walking up the 18th fairway into an amphitheater of applause this evening, had a bearing and manner that went beyond the question of whether he won a particular championship. For this place and time, he was a kind of king.

Behind him, Sutton was not a bad Prince Hal.