After weeks of growing tensions between Washington and Nicaragua's 8-month-old revolutionary regime, the United States decided that this weekend it was time to play hardball.

It sent in the Baltimore Orioles.

For two days and two games, the Birds took the revolution by storm, becoming the talk of the country, filling the sports pages and air waves and winning friends.

As a finale this afternoon near the bombed-out ruins of Leon, they did for the spirit of Nicaragua more or less what the Soviet hockey team did for the spirit of the United States. They lost.

In the Saturday game, at Granada, they had been held to a 1-1 tie (the game was limited to nine innings) by a Nicaraguan pitcher named Luis Cano, who finished the game despite being hit by a line drive.

Today though, in Leon, they faced three healthy pitchers who utterly baffled them with constant changes of pace. The Orioles lost 4-2 to the Nicaraguan all-stars.

"I just think a lot of these guys came down here expecting to meet a lot of sandlot ball players," said Orioles traveling secretary Phil Itzoe.

A uniformed Sandinista standing nearby suggested with a smile, "Well, we're little, but we certainly are good."

Of course, one could say that this was really just another couple of spring training games for the team from the United States. Really it was only half a team. The best of the Orioles went to New Orleans this weekend to take on the Yankees, and most of the 17 Birds who came to Nicaragua had seen more of Rochester and Charlotte than of Baltimore in their careers.

But, then, the Nicaraguans only cared about one major Oriole star and he was here -- Dennis Martinez who was born in Granada, Nicaragua, and who played there until he signed with the Orioles seven years ago. Nicaraguans have loved the Birds ever since Martinez started throwing their pitches.

In this country still trying to pick itself up and start moving ahead, the arrival of the Orioles seemed an occasion for recognition and competition. It might have been the World Series as far as the Nicaraguan fans were concerned.

One young Sandinista security gaurd wearing tattered fatigues and toting an Israeli-made submachine gun shook his head in amazement as the Orioles sauntered on to the field in Granada. "The big league. I never thought I'd live to see them here."

The Orioles' barnstorming visit had the active backing of the U.S. State Department and the Nicaraguan government. Washingtonians Douglas and Stephen Hellinger organized it, the U.S. International Communication Agency paid the $8,500 air fare, local businessmen covered the hotel bills and the Nicaraguan government provided transportation here.

At the start, few Nicaraguans thought their team had a chance against the champions of the American League.

"If we won," said one young man in the stands at Granada, "it would be a favor from them."

Still, from the first word that the Orioles might come, the talk on the streets of Nicaragua took a new tone. Conversations about alleged CIA plots to destabilize the Sandinista-led government gave way to speculation on batting orders and pitching styles. Whatever hostility generated by the failure of $75 million in U.S. aid to pass through Congress began to subside.

Aid has great importance to a nation ravaged by the 46 years of dictatorship, a devastating 1972 earthquake and a revolution that killed more than 30,000 people last year. But baseball is not just a pastime for Nicaraguans. It is a passion.

The same U.S. Marines that occupied Nicaragua on and off for almost 20 years beginning in 1912 and who ultimately installed the Somoza dynasty in power, also gave Nicaragua their taste for baseball. The game became almost as loved as the dynasty was hated.

Reporters who covered the civil war last spring and summer remember that behind the barricades during lulls, the young militia fighting Anastasio Somoza's National Guard would sometimes take out gloves and toss a ball around.

In the last two months organized baseball has again begun to flourish. The national sports institute says 3,000 amateur teams are playing in this country of 2.5 million people. There are no professionals.

On the field and in the dugout this weekend, it was clear that several of the players bore at least the emotional scars of the fighting. First baseman Julio Sanchez said that since he fought in the war, "my mind is still not ready to play. I never thought of baseball when I was with the Sandinistas, because I never thought I would play again."

Others, like centerfielder Apolinar Cruz, who is being scouted by the Orioles, played for the old Somoza team. But nobody held that against them today when they helped the new national team win.

The Orioles' Martinez also was affected by the war. His family, which survived, remained in Nicaragua throughout the fighting. As the war reached its peak Martinez's pitching fell apart. He said the two things were not related, that he had total concentration but bad luck on the field. But then, he said, "I would go back to my room and really worry."

On his home turf this weekend, Martinez pitched four perfect innings against his old teammates.

The Orioles came with some concerns of their own. Although the tour organizers had explained that Nicaragua is now one of the most peaceful countries in the area, not all the Birds were convinced.

"I understood the U.S. supported Somoza and these people really hate Somoza," said pinchhitter Terry Crowley. "I just thought it's really not that good a time to be coming down as a gringo."

The guns that are still everywhere in evidence did not help to inspire much confidence in the Orioles' first few hours here. At the ramshackle stadium in Granada, several discovered that one of the security guards was 15 years old. He looked 12, except for the submachine gun over his shoulder.

"I asked hin if he knew how to use it," said a Spanish-speaking Oriole tryout with a shiver. "He said he'd killed two National Guardsmen last year."

After the game, the young soldier handled the crowds surging onto the field like a professional.

And while the Nicaraguans obviously loved winning, it was also clear that -- as they came by the thousands and cheered the Star Spangled Banner almost as much as their own anthem -- they loved the Orioles just for being here, win, lose or tie.