On a day when the lords of American golf were unable to satisfy themselves or their large followings, an uncharismatic, under-appreciated player from Shoel Creek, Ala., took a major stride yesterday toward becoming "the man in the green jacket" at the 42nd Masters.

Hubert Green, last season's U.S. Open winner, riddled the fabled National course with seven birdies for a 65-206 that earned him a three-stroke lead over defending champion Tom Watson and second-round coleader Rod Funseth.

Lee Trevino, who shared Friday's lead with Funseth, faded to 72-211 after taking a triple-bogey 7 on the fifth hole. Arnold Palmer shot a 74, up to 216, while Jack Nicklaus still couldn't find his putting touch despite scoring 69 for 214.

Trevino is seeking to add a Masters to his one PGA, two U.S. Open and two British Open titles. Palmer has won here four times. Nicklaus is a five-time master of the Masters. They drew the galleries yesterday but Green produced the big shots.

"My putting was good, and my chipping got me extremely close on several holes," Green commented. "About the only close putt that didn't go for me was on 17, when it nicked the left side, but I can't complain, not the way I putted overall and the way the seven-foot putt went in on 18, (curling 358 degrees around the cup).

"It just nice," Green added, "to be in position to have to lose a tournament like this. I don't intend to."

Green is the second-leading money winner on the tour this year, behind Nicklaus, with victories in the Hawaiian Open and the Heritage Classic.

Gene Littler, a 70-210, is four strokes behind Green. Trevino, Dave Graham, Hale Irwin and Billy Kratzert are grouped at 211.

"Hubert is going to be a tough man to beat, the way he's uptting and chipping," remarked Watson, who shot a 68 in Green's twosome yesterday. Funseth agreed, saying: "I was happy with my 70 but I went from two ahead of Hubie to three back."

"I think," Watson quipped, "we're going to have to put a contract out on Hubert, the way he's going. You can be darn sure he's not goint to quit . . . and being in front by a few strokes over the closing holes here is a tremendous advantage."

Trevino will not soon forget his misadventures on the fifth hole. He was six under at that point, tied with Green.

"I decided to cut a three iron into the green," Trevino said, "and it went into the wilderness, back behind. I had to straddle a tree and hit a one iron with the black of the club, lefthanded, to get out of there . . . into a bunker in the front. I tried to nip it out of there, and couldn't, finally got on, and missed the putt from three feet.

"I'm afraid my (green) coat went out the window, right there "Trevino concluded.

Trevino will not soon forget his misadventures on the fifth hole. He was six under par at that point, having picked up a birdie on the third hole, and was tied with Green for the tournament lead. Then his headache developed.

The drive was good enough, over the crest of a hill, but his iron shot flew over the green. Trevino chipped back - into a trap guarding the front left side. His first attempt to get out of the trap failed. Once on, he two-putted from 20 feet for the triple-bogey seven that may well have ended his dreams of adding a Masters to his one PGA, two U.S. Open, and two British Open titles.

Nicklaus, Gary Player, Gene Sarazen and Ben Hogan are the only men to have captured all four of the Grand Slam events, a feast never accomplished in the same year.

The man who many thought might make a serious bid to sweep the Big Four this season, Nicklaus, would have been near the lead after yesterday's round if he could have putted reasonably well.

"It was one of the most frustrating days I ever had on the greens," Nicklaus declared. "I hit an awful lot of good putts, but nothing would go down. I missed four putts today from four feet to eight feet. Now, for me to have a chance tomorrow, I'll have to shoot a 64 or 65 and some of the other fellows would have to play not so good."

His most frustrating hole yesterday probably was the par-5 15th, where he drove over the green in two, chipped back four feet past the pin . . . and missed another putt.

"The greens still aren't fast," Nicklaus moaned. "They'll have to be faster tomorrow under the conditions. I think what's happened here this week was, with all the fertilizer that had been put on the greens, when it got real hot like it did, the grass just took off, growing, and they got slow."

Nicklaus' playing partner was Graham, who carded a 67 despite four-putting the par-3 sixth hole for a double bogey. Graham, an Australian, was three under at the time, after sinking short putts for birdies on the first, second and fifth holes.

"My seven iron to the green on No. 6 hit the upper slope of the green, about 20 feet from the pin, but it rolled all the way back to three feet off the fringe (about 50 feet from the cup)." Graham reconstructed. "My first putt was to within six feet. The next rimmed the right side and went three feet out. It had broken sharply, so I figured the one coming back would break the same way, this time to the right, only it went straight."

Graham recovered nicely to shoot a 32 on the back nine, featuring a 30-foot putt for an eagle on the 13th.

"If you can maintain your composure here, it's amazing what a 69 or a 68 or a 67 will do for you," he noted. "You have to be patient. I'm just happy the greens aren't glassy-fast as they have been occasionally here in the past. You couldn't have had a more perfect day than we had today."

Washington's Lee Elder shot a 37-37 - 74 yesterday, hiking his total to 222. Elder started off smartly, with a birdie on the third hole, but bogeyed the sixth, ninth and 10th before posting birdies on the 12th and 13th. Bogeys on 14 and 18 then put him two-over for the day.