A week ago, when Sergei Fesenko won the 200-meter butterfly and became the first Soviet man ever to win an Olympic gold medal in swimming, he said he had planned to retire after the current Moscow Games, but now felt obliged to carry on until he has a chance to prove himself against the American swimmers who did not come here.

"The fact that Mr. Carter would not let his athletes take part in the Olympics I think was very incorrect," Fesenko said of the U.S.-led boycott by approximately 50 nations in protest of the Soviet invasion of Afghanistan.

"But even with everyone here, I think I would have a chance to win," added Fesenko, who now intends to postpone his retirement until after the 1982 World Championships, where he expects to challenge world record holder Mike Bruner and the other powerful American Swimmers.

Consider the gauntlet thrown.

Soviet men have won the majority of medals, and the majority of golds, on the competition that ends Sunday at the fast and impressive Olympic swimming complex at Prospekt Mira.

They clearly are disappointed that the American men -- who won nine of a possible 15 gold medals in the 1972 Munich Olympics, and 12 of a possible 13 at the 1976 Montreal Games -- did not defend against the ascending Soviet hosts in their own pool.

The unmistakeable impression conveyed by the Soviets is that they could have at least held their own against all comers and very possibly smashed the American male domination.

"If the U.S. swimmers were here in the pool, I'm sure my time would have been the same," said the formidable Vladimir Salnikov, winner of three golds (400- and 1500-meter freestyle and 4 x 200-meter free style relay), after he became the first swimmer ever to break 15 minutes in the grueling 1,500 meters.

"So far, no one else has broken 15 minutes at this distance. If they can do it, invite them to prove it. For now, Salnikov is the only one to do it."

The Soviet men -- who had won five of nine possible golds, and 14 of a possible 23 medals overall going into tonight's swimming events, and had set four Olympic records and one world record -- are in the sixth year of a five-year plan for developing swimmers.

The Soviets added another gold and a bronze tonight when Robert Zulpa won the men's 200-meter breaststroke in 2:15.85, and Aresen Miskarov was third (behind silver medalist Alban Vermes of Hungary). The Soviets surprisingly were shut out of the 200-meter backstroke medals.

Once known solely for their breaststroke, in which they have seven of the top 12 men and three of the top five women in the world, they have embarked on an intensive campaign to gain world stature in other strokes.

The program initiated by the nationalcoach, Sergei Vaytsehoski, has borne more fruit and medals than many of the celberated five-year plans for Soviet agriculture and industry, which often have to revised. The Soviets started reaping world records in impressive numbers last season, and they currently hold the world standard in every freestyle distance between 200 and 1500 meters: 200, 400, 800 and 1500.

"It has taken a long time for us to progress," Vaytsehovski said last summer.

A muscular man of 51 with a rough crewcut that one British writer described aptly as looking "rather like an upstanding helmet of barbed wire," he is a former modern pentathlete whose 22-year-old daughter Elena was an Olympic diving champion at Montreal four years ago. He never coached her because, he says, "I am not really interested in diving -- a little boring, I think."

Vaytsehovski has been candid during the current Olympics about how the Soviet Union has overtaken a number of traditional swimming powers. They did a little nonsinister spying and copied the pattern of success.

"We decided that our coaches should travel around the world, to Australia, the United States, the German Democratic Republic and West Germany and look closely at all the different systems of producing swimmers," he said.

"Then we came home and made a combination of all the systems that would work for our own country and own teams."

Among the borrowed components was an adaptation of the American age-group system of competition, with built-in incentives designed to try to keep young swimmers interested in the sport as they grew older.

"We had to make sure we had a broad base.We have about 150,000 competitive swimmers in the Soviet Union, about the same as in the United States, and we built up a group of 300 swimmers at the national level in various age groups," Vaytsehovski told British writer Neil Allen.

International competition, was another integral part of the plan, and so age-group dual meets have been arranged annually with various countries, including both East and West Germany.

"This chance to have matches is very important for the young," said Vaytsehvski. "It keeps them in the sport because they have something, including travel, to aim for. Ten years ago we were keeping only about five percent of our swimmers after they grew older. Now we are keeping maybe 70 percent of our European junior champions, going on to the senior level."

The Soviets also have incorporated western training techniques in swimming, and combined them with the sophiscated East European expertise in sports medicine and bimechanics like the East Germans -- whose women had won 18 of a possible 24 medals, including seven of eight golds and had swept five events going into today's competition. The Soviets also now stress weight training for swimmers.

"We do more land exercises than before, some running and much exercise with special machines -- multigyms equipment from America," said Vaytsehovski. "Always we want to emphasize strength."

Vaytsehovski, perhaps from his modern pentathlon days, also believes in togetherness. Most of the Soviet swimmers are grouped in training according to stroke, but they all come together several times a year for massive swimming camps -- to build esprit and camaraderie.

The kidship was evident a couple of days ago when Salnikov won the 400-meter freestyle, then jubilantly embraced and kissed his teammates who finished second and third, ahead of the Brazilian he had expected to win the silver medal.

Salnikov is a personable 20-year-old, with a blond crewcut, high cheekbones and a radiant smile. He was beaming in the pool and, as he climbed the victory podium to receive his third gold medal, he waved to the adoring crowd with the bouquet of red carnations he held aloft in his left hand.

But as the Soviet National Anthem was played, and three Soviet flags -- yellow hammer-and-sickle on a bright red background -- were raised, he looked solemn and contemplative. He has a diploma in English, as an interpreter, and perhaps he was thinking"Bring on the Americans, we'll beat them, too."

The Soviets Do not like President Carter's boycott of their Olympics, and their hording of so many of the gold medals the U.S. had been expected to win in the pool is one way of saying, "In your face, Yanks."