"It must be something to do with the temperament of North Americans," suggested a Peruvian watching yesterday's big game between the Diplomats and the Cosmos-maybe some sort of confusion between money and passion.

The money was out there running around on the field all right, millions of dollars worth of feet and skulls.

But it was not until two overtime periods and the tie-breaking shootout (a North American contrivance calculated, no doubt, for just such effect) that there was even a hint at RFK of the rapid-fire passions, furies, ecstasies and agonies that pulse through soccer crowds everywhere else in the world.

And even elsewhere in Washington.

Scattered through the nearly 25,000 people in the stadium yesterday were hundreds of foreigners-and a few North Americans-who have played in the amateur leagues of the Washington area, who have soccer in their blood, and have, on occasion, seen it mean blood.

The problem, particularly in leagues where the teams bear nationalistic names, has not been how to generate passion, but how to control it.

Strictly enforced rules of conduct and high fines-for the crowds as well as the players-were put into effect over the last two years.

Before that, said one veteran amateur player from the West Indies, "there were a lot of fights within the field, a lot of fights outside the field, a lot of very strong reactions to whatever was happening. It used to be you would know the night before that you were going into a fight-the whole team and the spectators.

"I haven't seen one big fight yet without the spectators getting into it."

Most people agree that the actual violence is now under control, but emotions still run high. For some of the foreign players and spectators, Sunday morning amateur soccer matches around town are the only real recreation they have, mingling the intensity of an intrinsically exciting sport with longstanding national, cultural, athletic and sometimes personal rivalries.

Yesterday morning, for instance, it could be said that the little El Salvadoran town of Intipuca beat the world on a hard, dusty playing field at American University.

The players on the Intipuca City soccer team in the National Soccer League of Washington all come from one of the poorest regions of the poorest country in Central America (a country that, not incidentally, fought a war precipitated by a soccer match in 1969).

Some players on the team-for obvious reasons they are reluctant to talk about this-are living and working illegally in the United States to support their families in Intipuca.

Though the U.S. Immigration and Naturalization Service has not raided a soccer game since 1976 (El Salvador versus Peru in West Potomac Park, 24 players and spectators arrested and the INS subsequently banned from Park Service land for the havoc it wrought) there still is that lingering tension.

Virtually all of Intipuca City's players work long hours for low wages, many on shifts that last late into Saturday night and make it difficult for them to join in the matches the next morning.

"Sometimes," said team spokesman Fernando Leongo, "we don't have the whole team here until the last few minutes of the game."

The team was formed about four years ago by Sigfredo Chavez, one of the first of about 1,000 people who have come to Washington from Intipuca over the last decade. "We had too much people from Intipuca in this country and they all play soccer and this is a good thing for Sunday," Chavez explained.

The team joined the National Soccer League in 1977, Leonzo said, and last year was edged out of the No. 1 slot in the second division by a single cumulative point. The winning team, then, was the International Student Soccer Club of American University.

This year, Intipuca City already has clinched the second division title and will move to the first division next season. The International Students have, meanwhile, been suspended from the league because one of their players hit a referee during a game last December.

Yesterday was a grudge match, pitting the relatively small Intipucans against AU's lanky team of men from Iran, Spain, Tanzania, Tunisia, Algeria, El Salvador, Argentina, Colombia, Syria and the United States.

AU lost an important player early in the game when he executed a spectacular flying scissors kick and broke his wrist on a bad landing. But the students nevertheless scored the first goal.

"This always happens to us, "said Leonzo," "but wait."

Godofredo (Chiqui) Hernandez-a busboy at a Georgetown restaurant and "the most valuable player" in the second division this year-scored for Intipuca to ecstatic cries of "Ole," as if a bull had been slain by a matador.

The score was tied, 2-2, near the end of the second half when Raul A. Hernandez, a housepainter for six days of the week, won the match for Intipuca.

The whistle blew, the crowd of Salvadorans along the sidelines rushed onto the field to hug the team. Finally, when the shouting and laughing died away and the mandatory pictures had been taken to send back home, the players retired into the bushes to change out of their faded red uniforms, pile into cars and go see the Diplomats and Cosmos.

"You people," one of the Salvadorans told a North American reporter as he was leaving the field, "are still just learning about this game." CAPTION: Picture 1, Alan Green, who had both goals for diplomats, dribbles around newest Cosmos player, Wim Rijsbergen of Holland, By Richard Darcey-The Washington Post; Picture 2, A player from Intipuca City wins the race for the ball with American University trio. Intipuca City won game, 3-2. By Kenneth Stancil-The Washington Post