An impressive nine-point win over Seattle on Sunday, combined with a stunning second straight loss at home by the Cosmos, had the Washington Diplomats talking about a run at first place yesterday.

The 3-1 Diplomat victory over the Sounders at RFK Stadium gave them a 15-7 record, good for 133 points and second place in the National Conference East. The Cosmos, 4-2 losers to Vancouver, now are 16-6 for 146 points.

"Who would believe they could lose two in a row at home?" asked Diplomat General Manager John Carbray. "Maybe they aren't so invincible. If we win Wednesday and they lose in Fort Lauderdale, it's going to get interesting."

Things already are interesting enough as far as the Cosmos are concerned. Not only were they beaten by the Whitecaps, who come to RKF Wednesday at 8 p.m., they also had their reputation tarnished by a bench-clearing, 15-minute melee that ended with Pele, their former hero, turning from spectator to combatant.

Cosmos Giorgio Chinaglia and Eskandarian were ejected, meaning each will have to sit out a subsequent home game. Julio Mazzei, technical director of the Cosmos (their euphemism for coach), blasted the officiating after the game and vowed to start the two ejected players Sunday against Minnesota.

North American Soccer League officials were taking a wait-and-see attitude yesterday towards Mazzei's statement, the fight and the Cosmos' formal protest of the game. League spokesman Jim Trecker said Commissioner Phil Woosnam had asked to see films of the game before taking action.

"If the commissioner takes any action, I imagine it won't be until the end of this week at the earliest," Trecker said. As for Mazzei's threat to play the ejected players, Trecker said, "Right now that's still hypothetical. But certainly that kind of action would be a direct violation of league rules."

Washington officials, including President Steve Danzansky, were on the phone to New York trying to learn details of the brawl which broke out early in the second half.

It ended with Pele, who was watching the game from the Cosmos bench, apparently coming to Chinaglia's aid just before the volatile Italian was led from the field.

Diplomat Coach Gordon Bradley, who listened to the Cosmos game on a New York radio station, was far more concerned yesterday with getting his team ready for Vancouver, the Western Division leader with a 14-8 record.

With a two-game California road trip coming up after the Vancouver game, that contest is a must win if the Dips hope to remain within striking distance of the Cosmos.

Vancouver achieved two milestones with its win Sunday night: The Whitecaps are the first team to beat the Cosmos twice in a season since 1976 and the loss was the first time since that same season that the Cosmos had dropped two in a row at home . . . Dips are hoping left back Tommy O'Hara, who suffered a foot injury in practice Friday, will be back for the Vancouver game . . . Sweeper back Rene Breevoort will sit out Wednesday because of penalty points but Jim Steele, who missed the Seattle game for the same reason, will be back.