The Washington Diplomats, who received the wonderful news yesterday that international soccer star Johan Cruyff will return to play here July 1, could have used a bit of the master's magic last night.

Fresh off a big victory in Chicago, the Dips gave their Eastern Division rival Cosmos fits before the defending Soccer Bowl champions took over the game in the second half and stole a 2-1 North American Soccer League decision before 36,875 at RFK Stadium.

Washington (9-7) got the benefit of a questionable call to tie the game at 1-1 on a penalty kick before Giorgio Chinaglia scored the winning goal.

In two previous meetings with the Cosmos, which the teams had split on a home-and-home basis, Washington held Chinaglia, the league's leading scorer, to no goals and one assist.

But the top scorer in the league's history finally broke a string of what he called frustrating minutes when he tapped a 12-foot shot into an open net at 68:22 to give the Cosmos their fifth consecutive win. He apparently scored a minute later, too, but that goal was nullified by an offsides call.

"Everyone has ups and downs," said Chinaglia, who undoubtedly will savor this, his 18th goal of the season, a bit longer. "Washington had done a good job against me, and I had become a bit frustrated. I thought I should have scored in the first half. I had a good chance early but I messed it up. I finally got one."

Chinaglia had a little help, both from teammate Chico Borja and Dip defender Eddie Colquhoun. Cosmos defender Wim Rijsbergen set the play in motion, sending a long, high ball toward the Washington penalty area. Borja controlled the ball, faked Colquhoun out of the play and tried to sneak a shot past Dip goalkeeper Jim Brown, who had no choice but to come out to attend the all-alone winger.

Borja's shot was rolling slowly toward the net before Chinaglia raced up and kicked the ball home.

"Giorgio was there to make sure," said Borja, who also assisted on the Cosmos' first goal. "I faked him (Colquhoun) a little, pushed him a little and got off a shot, a very weak shot. Maybe it was hit hard enough to roll in, maybe not. It looked like a pass, but it was a shot."

Following Chinaglia's goal, the Cosmos tightened up and choked off several threats by Washington. The open shots that rained on the heads of the scuffling Cosmos defenders in the first half ceased. The few that looked promising ended up in the hands of Cosmos goalkeeper Hubert Birkenmeier. He made only five saves, but all were tough.

"Birkenmeier was the key," said Washington Coach Ken Furphy. "We played great soccer, especially in the first half. If we play like that every week, no other team can beat us."

The Cosmos, who raised their season record to 14-4 and lengthened their point advantage over Washington to 47, looked very beatable in the first 55 minutes. As in the 3-2 triumph here, the Dips dominated play and maintained pressure on the Cosmos. But in the first half of this one, they did everything right except score.

Peter Carr, David Bradford and Ross Jenkins, who accounted for nine of Washington's 10 first-half shots, had excellent opportunities. A shot by Bradford was tipped just over the top of the net and, later in the first half, a header by Jenkins barely went wide from close in. Jenkins had another header attempt from 10 yards away that Birkenmeier somehow managed to deflect.

Washington dropped its guard for an instant late in the first half and the Cosmos capitalized. Tricky Roberto Cabanas outfought Colquhoun for a pass from Borja and sent it under a diving Brown to put the Cosmos up, 1-0, at 40:52.

The Dips tied it at 50:50 on a penalty kick by Malcolm Waldron. Rijsbergen was whistled for pushing David Baralic out of bounds along the Washington end line. The Cosmos screamed long and loud enough to earn two yellow cards, one by Robert Iarusci, the other by Francois Van der Elst.

"I didn't do a thing," said Rijsbergen. "Yes, I had my hand on him but he was leaning on me and fell. It was a hopeless call."

Several of the Washington players thought Chinaglia's goal may have been offsides.

But Washington's Paul Cannell, who subbed late in the game, said Chinaglia's first goal should have been nullified and the second one was good. c