The Soviet Union tonight portrayed the U.S. decision to lift the grain embargo as a stinging defeat for the United States in its policy of putting pressure on Moscow.

The official Soviet news agency Tass was unusually quick to announce Resident Reagan's order canceling the embargo on grain sales. But it did not mention that the embargo had been imposed as retaliation for Soviet intervention in Afghanistan.

Tass insisted former president Jimmy Carter's embargo order had had no effect on the Soviet Union "The embargo caused serious economic damage, not to the U.S.S.R., but to the United States itself," Tass said. dIt added that the embargo "put the United States in an unfavorable light as a rather unreliable trade partner."

In Ottawa, Canadian Prime Minister Pierre Trudeau said lifting the embargo probably would have little impact on international markets. Canada lifted its embargo last fall.

"The effect will already have been discounted by the markets," Trudeau said at a news conference. "In any case, even when the embargo was on, the U.S. had record sales to the Soviets."

[Australia lifted its partial grain embargo against the Soviets early Saturday morning, according to a United Press International report quoting a government statement.]

["Australia's policy of restraining grain sales was in support of the U.S. action and was conditional upon America continuing this policy," the statement said.]