Alexander Dityatin of the Soviet Union, who this week won more gold medals in a single Olympics than anyone else in the history of the modern Games, is lucky as well as skilled. Men's gymnastics, in which he won his eight medals, was affected more than most sports by the U.S.-led boycott of the Moscow Games.

Dityatin is the reigning all-around world champion, having edged American Kurt Thomas for that title last December in Fort Worth. He probably would have won the all-around gold medal even if the traditionally strong Japanese and ascending U.S. and Chinese teams were here, but his other medals would have come much harder.

In their absence, due to the Soviet invasion of Afghanistan and the subsequent boycott, Dityatin won three gold medals (all-around, team champion, rings), four silver (side horse, horizontal bar, parallel bars, vault) and one bronze (floor exercises).

The previous high was seven medals, all gold, achieved by American swimmer Mark Spitz in the 1972 Games in Munich, and by Soviet gymnast Nikolai Adrianov, four gold, two silver, one bronze in the 1976 Olympics in Montreal.

Before the boycott, Thomas was asked if he could beat Dityatin in Moscow and he said: "I can. I came within a tenth of a point last year (in the all-around at the World Championships), and I think I'm within a tenth this year." Thomas -- who won the gold medals in horizontal bar and floor exercies at Fort Worth -- and his teammate Bart Conner might have denied Dityatin a couple of individual apparatus medals.

Despite the taint of less-than-Olympian competition, however, Dityatin is an extraordinary gymnast -- so powerful that he seems to bend the apparatus to his will and make exceptionally difficult routines look easy.

"He is like a big machine that just chugs along, turning out 9.9s as though he doesn't know how to do anything else," Conner said last year of the man who supplanted Andrianov as the gumnastics hero in the Soviet Union."He never makes a mistake, and his upper body strength is incredible."

Ironically, Dityatin, who will turn 23 in 11 days, began gymnastics as therapy because he was a stoop-shouldered child. Now a physical education student at a state school in the native Leningrad, he devotes at least 4 1/2 hours daily to a sport he rules with controlled grace.

"His performances are distinguished by safety, difficult elements, exactness and elegance," the Soviet coach said of Dityatin after his tour de force this week.

Diyatin is nearly 5-foot-10 and 150 pounds, the tallest world-class Soviet gymnast since the great Victor Choukarin, who won the all-around gold medals in 1952 and 1956.

Dityatin has been accused of leaving out the most difficult elements of his routines when protecting a comfortable lead. At Fort Worth, for instance, he omitted the exquisitely difficult flyaway half-somersault from his horizontal bar routine, to minimize the risk of a fall that could have allowed Thomas to sneak ahead and win the gold medal.

At his home Olympics, before big andknowledgeable crowds at the Lenin Sports Palace, Dityatin strutted his best stuff, however.

"He was fantastic," said a Hungarian gymnastics expert admiringly. "His routines were very complicated, very difficult, and he performed them almost perfectly. He is a great champion."

Diyatin has been called "the Soviet pin-up boy," and his smiling photo undoubtedly will be plastered on posters throughout the Soviet Union -- his medals around his neck, a la Mark Spitz. Unlike Spitz, he won't be doing any milk commercials, however, and won't have the opportunity to bomb on the Bob Hope show.

That is not the Soviet way, even for a Merited Master of Sport.