A strange thing happened here Sunday: the Cosmos lost a soccer match. Then an even stranger thing happened: not only did they accept defeat graciously, they almost seemed to revel in it.

Moments after the Chicago Sting had beaten the Cosmos in double overtime, 3-2, in an exciting match before 42,385 in Giants Stadium, the door to the visiting locker room swung open and three men walked in. First came Steve Ross, president of Warner Communications, the Cosmos' parent company. Right behind him were Nesuhi and Ahmet Ertegun, chairman of the board and president of the Cosmos, respectively.

Around the room they walked, glad-handing everyone in sight, offering congratulations on a job well done. Two years ago, when the Vancouver Whitecaps eliminated the Cosmos from the playoffs, everyone in the organization -- with the exception of Ahmet Ertegun -- holed up in the locker room for 40 minutes, then snarled at anyone and everyone when the doors finally opened.

Ross and the Erteguns have not developed a sudden desire to spend Warner's millions and lose money. But they know that Cosmos fans have become bored by the procession of mediocre teams the North American Soccer League parades through Giants Stadium. Two years ago, the Cosmos expected a minimum of 50,000 customers just for opening the gates. When they played a class team, the crowds were closer to 70,000. But that has stopped.

"There's no doubt that we need competition," said Rafael de la Sierra, vice president of the team. "We need for the teams in this league to come in here and play us tough. Our fans know when they have gotten their money's worth. Today, they got that."

The match Sunday stood in sharp contrast to the previous two home games. Two weeks ago, they beat Washington, 1-0, in a match that had all the creativity of a television commercial. One week ago, they easily defeated Toronto, 5-1, another of those routine routs that is keeping spectators away.

Those games drew a total of 61,000, a figure that would cause ectasy in any other city in North America. Here, it caused anguish, head scratching and near panic.

Clearly, the fad has worn off. Pele is gone. Franz Beckenbauer is gone. Carlos Alberto is gone. They are three of the most luminous names in soccer history. In their place are Francois Van der Elst, Seninho and Bob Iarusci. Very good soccer players, but not legends.

Still, there is no other team in the NASL with anywhere near the talent of the Cosmos, who come to Washington Saturday night to play the Diplomats. They may be less glamorous, but they are just as effective. In fact, with fewer superstars, there is also less rancor. The team may be better in terms of triumphs and losses before the season ends, bettter than the teams that won 24 games each of the last three seasons.

The Cosmos have an 8-2 record. Less than a third of the way into the season, their lead over the second place Diplomats is 24 points. No one in the NASL is within 18 points of them.

"The fans here are spoiled," said Iarusci, a former Diplomat. "They expect us to come in here and play perfect soccer, which, of course, we can't do. When we make a mistake, any mistake, they boo. How many Beckenbaurers are there? We're a very good soccer team, but we aren't God."

The Cosmos are now entering a new phase -- certainly not starting over by any means, but marketing a different product. This year's team is one of the youngest in the league. Among the regular starters are Ricky Davis, 23, Roberto Cabanas, 21, Julio Romero, 20, and Jeff Durgan, 19. The roster is full of young Americans who will be expected to step in during the next few years. While the rest of the league talks about Americanization, the Cosmos have actively pursued it.

"We've always believed that the key to the game eventually is good American players," de la Sierra said. "We could probably average 10,000 more fans per game by signing older stars, people like (Johan) Cruyff. But if we had signed Cruyff we would have a 34-year-old player in the place of a 21-year-old. I would rather give the chance to the 21-year-old who can be of value to us for the next 10 years."

The Cosmos marketing strategy in the late 1970s was simple: buy as many players from as many different countries as possible. The ideal lineup was 11 players from 11 different countries. That way, New York's large ethnic community would be attracted. The Cosmos figured that if the ethnic groups came first and produced high attendance, the bandwagon-jumping people of New York would follow.

They were right. Now, the emphasis is more on the young players, for two reasons. First, the Cosmos want to build names who will sell tickets in years to come. Second, they are trying to strengthen their team for international play.

"For a lot of years people said the Cosmos were just a circus," Ahmet Ertegun said. "We were considered a team of old stars, nothing more. Now, we're playing the game at a faster pace because we have a much younger team. That creates more mistakes, but, I think eventually it will create more exiciting soccer.

"There was no way we were going to maintain the excitement level at the height it reached during 1977-'78-'79. Every team, every sport has peaks and valleys and we're in something of a valley right now.

"Next year, though, is a World Cup year and I think that will rekindle a lot of interest in soccer in this country even though the U.S. did not qualify. People know down the road the U.S. will qualify. The development of home-grown talent will cause our next explosion."

Today's Cosmos are an almost comatose bunch compared with teams of the past. When Alberto, who had feuded openly with Coach Hennes Weisweiller, was released at the start of this season, the only real character left on the roster was Giorgio Chinaglia.

But there seems to be no one left for Chinaglia to feud with. The coaches he battled are gone. So are the players. Now, Chinaglia marches around the locker room in his robe while the Erteguns pat him on the back and tell him, 'Good game,' regardless of the outcome. All is tranquil.

"I'm happy now, I've always been happy here," said Chinaglia, who is defensive when he hears implications that he has a say in team policy. "We have a great coach now and a great team. We play well together.

"The difference between the Cosmos now and the Cosmos when I got here is unbelievable. The team now is so much better. The reason is that we are a team, not just individuals running around trying to outscore each other. It is much better now."

In the old days, the Cosmos were bad winners and horrid losers. Shouting matches in the locker room were not unusual. Players regularly complained because they were benched. Now, the Cosmos win efficiently, answer questions politely and go home.

"I think this is more exciting because we're settle into a pattern and into reality now," Ahmet Ertegun said. "We've worked hard to build this team and we'll keep working hard to make it better."

The Cosmos are not merely a soccer team. They are a corporate entity that Warner uses to gain entry into foreign countries. But the 25 games -- regular season and international exhibition matches -- they play in Giants Stadium are still their financial backbone. Declining attendance is a major reason for concern.

"The Cosmos are the best thing this league has," Chicago Coach Willy Roy said. "I think we all know how important they are and we're all glad when they do well. We want to see those big crowds. The league needs them." w

For several years, the Cosmos were despised by the rest of the league because of the haughty, pretentious manner of many in the organization. Now, with the NASL ship taking on water, the league is looking to the Cosmos as a life raft.

"Once people resented the Cosmos," Terry Hanson, Atlanta vice president, said. "Now, we know how important they are to the league. We need them strong. But don't forget, they need us strong, too. The better the league is, the better off they are in the long run.

The Cosmos could not agree more. With a 76,000-seat stadium, they need fewer Torontos and Atlantas and more Chicagos coming to town. The New York area soccer fan now knows the difference between steak and hamburger and routine routs become a bore after a while.

"Great win," Steve Ross said Sunday, shaking hand with Roy. "Congratulations. It was a great day."

Undoubtedly, Ross meant for everyone.