The Swedish ambassador played tennis last night instead of going to the big party at the Soviet Embassy to celebrate the 64th anniversary of the Russian Revolution.

In the wake of the furor over the Soviet sub grounded in a restricted military zone off the Swedish coast, Count Wilhelm Wachtmeister, the Swedish ambassador in Washington, decided to stay on neutral ground on the tennis court -- "where no submarines are sighted," a member of the embassy staff dryly observed.

The Soviet Embassy's annual reception to celebrate the Great October Socialist Revolution (held in November because of a calendar shift) is one of the big splashes on the Washington circuit and often a barometer of the political and diplomatic climate.

Wachtmeister's decision to play tennis (he lost, although he played a "marvelous game -- too much firepower on the other side" was the report) came as Sweden's two Scandinavian neighbors, Denmark and Norway, announced they would join Sweden in directing their ambassadors to boycott today's military parade in Moscow marking the anniversary.

Danish Ambassador Otto R. Borch came to the Russian reception last night but brushed off an inquiry about his presence with: "Enjoy yourself. It's a party."

About 1,000 invitations went out for this year's reception. It turned out to be a rather subdued party in comparison with last year's, when former president Richard Nixon, making his first appearance on the Washington party circuit since his resignation, took over the party.

Soviet Ambassador and Mrs. Anatoliy F. Dobrynin were in the receiving line to greet the guests. There was a sprinkling of senators and State Department officials, including Sens. Alan Cranston (D-Calif.), Henry (Scoop) Jackson (D-Wash.) and Claiborne Pell (D-R.I.) and Walter J. Stoessel Jr., undersecretary of state for political affairs and former ambassador to Russia.

Among the guests were Amanda McKerrow and her parents from Rockville. McKerrow, who won a gold medal in the Fourth International Ballet Competition in Moscow in June, is getting ready to dance the Sugar Plum Fairy and the Snow Queen in "The Nutcracker Suite" for Christmas.

Among the Soviet Embassy staff members at the party last night was Vladimir Mikoyan, grandson of Anastas I. Mikoyan, the former president of the Soviet Union, who died three years ago at the age of 83. The first volume of his papers and diaries is expected to be published next year by the International Universities Press.

The young Mikoyan had a story to tell about his grandfather's visit to the United States in 1959 when he went to Detroit and wanted to meet the "great American capitalists."

Among them was Henry Ford II. After a ride in a Ford car ("the driver said he kept asking to go faster") and a tour of the assembly plant, Mikoyan and Ford were about to part.

"I'd like to give you the latest model of our car as a present," the auto manufacturer told his Russian visitor.

Mikoyan, demurring on accepting such a gift, said he would have to pay for the car and asked the cost.

"Oh, about 50 cents," Ford replied.

Mikoyan pulled a dollar bill out of his pocket.

"I have no change," said Ford.

"That's all right," said Mikoyan. "I'll take two cars."