It was the kind of situation that sentences men to breaking down, not breaking par.

Again, the heat was condemning today, a typical tiptoe through Tulsa at 102 degrees. And the par-70 Southern Hills Country Club was its usual conspiring and conniving 6,682-yard self.

So Raymond Floyd just played it cool. Cool and straight.

Missing only three fairways, two greens and no opportunities, Floyd shot a course record 63 today to take a three-shot lead over Bob Gilder and Greg Norman in the 64th PGA Championship.

"It's the best round of golf I've ever played," is how Floyd depicted his 33-30 masterpiece. "I've had two weeks off. I'm rested. This isn't a surprise to me. I knew my game was in shape."

The record book assessed Floyd's round this way: it was the best first-round PGA Championship score, breaking Bobby Nichols' 64 in '64; it also tied Bruce Crampton's second-round 63 in 1975 for best 18-hole PGA Championship score.

Four shots behind Floyd are Nick Faldo, Rex Caldwell and Fred Couples (who shot a PGA record 29 on the back nine). Vance Heafner, Mark Pfeil, Jim Simons, David Graham and John Jackson are at 68; Calvin Peete is among six at 69. Only 17 of 150 bettered par.

While Floyd was embarrassing the course (he had nine straight 3s, from Nos. 6 through 14), the course was embarrassing almost everyone else.

There was Jack Nicklaus (74), depositing a five-iron fairway shot into the pond by the 13th green. Of the double-bogey hole and his miserable round in general, Nicklaus said, "Basically, I got what I deserved. I'm not history yet. But I feel like it."

There was Hale Irwin (73) mis-hitting a six-iron from the 15th fairway to the 16th tee, then chopping a chip from the 16th tee, past the green, over the trap and by the leader board. It's the closest Irwin, who has earned $2 million in his career, got to the leader board today.

Then there was Tom Watson, here in search of his first PGA title and his record-tying third Grand Slam victory this year. Today, Watson shot 72. In a sweat and in a struggle, he said: "The golf course won today."

By the time Watson teed off on the first hole, Floyd was in the interview tent, telling the press, "The fact I'm sitting here at seven under puts pressure on the guys just getting started. If they bogey the first hole, they are already eight shots back."

Floyd ranks fourth on the 1982 tour earnings list ($240,409) and has already won the Memorial Tournament and the Danny Thomas-Memphis Classic. Today he played a classic round: 11 pars, seven birdies.

After parring the first six holes, Floyd, 39, set off on a streak that pared par again and again. He birdied Nos. 7, 9, 10, 12, 13, 16 and 18.

With the heat seemingly hot enough to split the woods and melt the irons right in his hands, Floyd merely kept a wet towel around his neck and his drives in the fairway.

Floyd's birdies on No. 12 and No. 18--Southern Hills' most feared and revered par-4s--place his round in perspective.

The 444-yard 12th is a dogleg left with a green protected by a creek in front and three traps around it. Arnold Palmer, who shot 74 today, has called this one of America's best par fours. He made the hole famous in the 1970 PGA, when he put his second shot into the weeds by the creek, then kept his shoes on while standing knee-deep in water to hit his shot. He said then, "I was worried about a snake biting me in the foot."

Today the 12th hole made numerous players snake-bitten. Nicklaus and Watson double-bogeyed it. Tom Kite (73) and Bruce Lietzke (73) bogeyed it. So did many others.

Floyd simply hit his driver 260 yards down the fairway, then dropped a five-iron within 15 feet of the hole. Then he bagged his birdie.

On the 434-yard 18th, a severe dogleg right, with a fairway that rolls unforgivingly to the right and a green that tilts errant putts somewhere near Oklahoma City, Floyd hit another excellent drive, then dropped a six-iron to within 10 feet of the hole. Then, another birdie.

Floyd, a man known for holding a lead once he gets it ("I'm more aware when I'm ahead early, that's all,"), said of his round that broke the course-record 65 he and Lee Trevino shot in 1970, "I'm much more in control now than ever before. Maybe it's maturity, maybe it's experience. It is my 20th year on the tour.

"I'm not an analyzing person, but you have to recognize your strengths and liabilities. Every player will say Nicklaus has beaten them through the years with his head."

Today, Nicklaus was scratching his head. He played the final 11 holes like the Americans played the Battle of the Bulge: from bunker to bunker. He also spent his share of time in the rough of Bermuda grass.

"The last time I remember any rough being this bad was the last time I played here," said Nicklaus.

Gilder, who shot a enviable round of equilibrium (33-33), said of the merry minority who bettered par, "This golf course will catch up with them. I'd be happy to finish the tournament at four under."

But cool Ray Floyd played it straight. "I don't think the way I'm playing is something that will go sour in my sleep tonight," he said. "It's the best golf I've ever played. It's a great time to play it, too."