The most perplexing figure at the Masters may be Severiano Ballesteros, the 1980 champion who enters Monday's final round one shot out of the lead.

Ballesteros, who turned 26 Saturday, is a study in sweet and sour.

His smile is charming. His golf game is a delight to watch. His drives are as long as any other human's. His daring style and bold putting touch make him riveting.

In a sport with many bland players, Ballesteros is a crowd-pleaser; today, after missing a putt at the 17th, he fell to the ground as if shot. Even his flaws--a tendency to the wild hook, a distinct moodiness when a bad swing or a bad break arrives--make him fascinating.

Ballesteros' smile and his gentle humor are delightful. Asked today if his victory here in 1980 would make another triumph easier, he said, "I think it was easier the first time than this time, because I have already won that one."

All this draws us toward Ballesteros. However, there is a sour, almost petulant side to Ballesteros. That side has also been on display here this week.

"People (here) want to see my bad shots. They do not want to see my good shots. I believe that," Ballesteros said Thursday.

Ballesteros is willing to say, as he did last week, that he won more money than any golfer in the world last year. On the other hand, he is not willing to admit he made his fortune by accepting pretournament guarantees and by beating up the improved, but still inferior competition in Europe and the Far East.

By playing only eight events a year on the tough PGA Tour, Ballesteros has opted for the easier money and more familiar life style of Europe--a reasonable decision. However, he is not comfortable with all the implications of that decison; American pros and fans will never accept him as a preeminent player while he's feasting on small-timers.

Yet Ballesteros, who has also won the British Open, fiercely wishes to be considered the world's best player.

This inherent conflict makes him testy as soon as he tees it up in the United States. Ballesteros insists he gets homesick. Asked why he doesn't play more in America, he said, "Ask the American players how many weeks in a row they can play in Japan."

This afternoon, after an erratic but game 73, Ballesteros was asked where, in the whole world, he most liked to play.

"Here," he said, meaning Augusta National.

Why?

Slyly, Ballesteros needled his critics, saying, "Oh, you know I am a very wild driver. This is the only course in the world that is wide enough for me. Every fairway is 200 yards wide, so I can use my driver."

Then the other, sweet Ballesteros suddenly appeared.

"I think this (tournament) is fantastic. The people are wonderful. The course, too. This looks close to my (home) course in Spain. The green grass, the hills, the flowers, the beautiful trees," said Ballesteros with feeling.

"I get very familiar on this place," he said, showing the open, unsuspicious smile that some feel he shows too seldom when he golfs in the United States.