Twenty-four hours before the start of the 42nd Masters Golf Tournament, there was Jack Nicklaus holding court at National tee time, telling the golfing world - and his 77 rivals - that Jack Nicklaus never has played this good.

"My game is better now then it's ever been," the five-time masters champion declared. "I had as good a spring as I could possibly hope for. Probably the best I ever had. I hit the ball pretty well during those four weeks (firsts at Jacksonville and Inverrary, second at Doral and Los Angeles), but I feel I could hit it better . . . and I think I am hitting it better now."

His caddy said Nicklaus was 22 under through five practise rounds.

"Well, maybe Willie (the caddy) along the line," Nicklaus said. "But I am very confident, coming in here. I'm not unhappy with any part of my game, including my short game."

Well, now, without invoking the name of Bobby Jones or Cliff Roberts, sixth green jackets, 72 holes early, or play out the tournament? Nicklaus is not a braggart. He is the best. And when the best says he's playing better than his best, when then?

"He's got them scared to death," says Gene Sarazen, an old, old pro who didn't scare easily. "He's got them on the defensive. For the first time. Ithink Jack can win the Grand Slam. I'ts the best chance he's had in his life."

Nicklaus is 38. "Most of my golf is behind me," the Golden Bear submits, but it is obvious he is not thinking about hibernation. Certainly hot here, at the Masters, on a course made for his booming drives and delicate putting touch.

"Jacks got to be in a super frame of mind, the way he's playing," Lou Graham said. "This course favors the big hitter. The fairways are relatively wide. The big hitter can really turn it loose, and not have to worry about the rough or anything like thet.

"You got to hit some good irons, too, at several holes," Graham added. "You got to put the ball in the proper at it on position to get a good putt at it on these big greens, and the greens can get slickish, but the big thing is turnning the ball loose, off the tee. That's the all-important theing here."

Graham, the 1975 U.S. Open winner, is not among those ready to concede to Nicklaus.

"Tom Watson's let down the last few tournaments, but that doesn't mean anything," Graham said. "As this tournament comes to an end, Watson will have a chance to win. He's longer than Nicklaus, and all it takes here is to play the first hole real good, and you go on from there.

"Golfers are a little crazy, you know. They get down on themselves quickly, but they get up just as quickly. It doesn't take lot to change them. The mental attitude can charge faster than the weather," Graham added.

This Masters is to be played in 80 degree temperatures. One again, the field is not as strong as the hype suggests. Ten of the 78 contestants are foreign players here by special invitation. Several are of dubious distinction.

The 13 ways for U.S. players to qualify seem a little to amateurish, a little hapazard and much too harsh against the many talented young men on the PGA Tour whose only failure, although playing well, has been not to win a tournament since the 1977 Masters.

"Admittedly, this is a weaker field than some other tournaments we play," Graham noted. "I think everybody would admit that. There are players, certainly good enough to be playing here, who just didn't get in under the rules."

What they miss, by not being here, is the prospect of meeting Nicklaus coming off a two-week rest, with Watson, Hubert Green, Hale Irwish, Tom Weiskopf and Ben Crenshaw, among others, having taken one week off to prepare for the year's first major event.

Such recognition by the top players is what makes a tournament. Such respect can not be designated by a committee or bought with higher purses.

As for this tournament, it's business as usual. All for rounds are sold out. The course may not be as difficult as the hosts would have one beleive, out it is a spectatorial treat, providing greet vantage points from which to view the action on "Red Dogwood," "Magnolia," "Juniper," "Carolina Cherry," "Azalea" and "Chinese Fir," several of the aptly named holes.

The front nine is a place to build confidence. Of the eight most difficult holes ast year, only Nos. 4 and 5 are on the front side. All four par 5s - the second, eighth, 13th and 15th - are middle iron at that on 13. These four holes played 159 under par last year.

No. 11 provides the first sight of water. It and No. 10 are the toughest par 4s, but it is No. 12, "Golden Bell," a 155-yard par, 3, that probably is the shortest and deadline hole of all.

The narrow, canted green is guarded by Fae's Creek. There is a trap on the slope from the creek to the slightly elevated green, with two big traps behind the green. From the tee, there's only a prime 35-foot-deep ribbon of green to work with. It's frightening. The only thing worse is to be in one of the traps at the back of the green, hitting toward the water.

"A man can age fast there,= said Watson, the defending champion who was golf's player of the year in 1977. Watson was 27 when he won here. He does not sound as happy at 28.

"I'm not as excited as I was last year, because I'm not playing as well," he said. "I'm having a little trouble with my swing. I haven't lost it. It's just hiding in there somewhere . . . until I find it again somewhere."

Severiano Ballesteros has been offered a special invitation to join the PGA TOur full time. The young Spaniard has 60 days to accept or decline the bid. He won the Greensboro Open last week, and had intended to return to Europe shortly, but he's reconsidering his position. Ballesteros failed to graduate from the Tour's qualifying school in 1975.

Next year's Masters will be held one week later than usual, April 12-15, to accmmodate television scheduling.

Maintenance crews have cut the fairways to seven-sixtheenths of an inch, the grass on the tees to seven-thirty-seconds and the greens to one-eighth. The course is "equal to its best."