The Washington Diplomats, still smarting from a 3-1 whipping by the Los Angeles Aztecs Wednesday night, began sniping at each other yesterday as the tension began to mount for Sunday's NASL playoff rematch.

"There's a lot of little problems, what normally would be petty problems, but right now they're amounting to more than that." Coach Gordon Bradley admitted. "We need to have everyone concentrating on nothing but this game right now. It's natural this time of year, but bad for us right now."

The Dips will have their backs to the wall Sunday when they face the Aztecs at 2:30 p.m. in RFK Stadium. If the Aztecs win the game, they will sweep the series, 2-0. If Washington wins, the teams will play a 30-minute minigame to break the 1-1 deadlock.

Included among the Diplomat problems yesterday were:

Complaints by the defenders about the play Wednesday of the midfielders, specifically Joe Horvath and Sakib Viteskic, who, the defenders said, did not help out enough defensively when Los Angeles was pressing.

Sniping back and forth between several of the club's British players and Viteskic. Bradley and Viteskic met yesterday morning to discuss Viteskic's play Wednesday and the problems between Viteskic and the British players.

The continuing battle between Bradley and team captain Jim Steele. With Don Droege out of practice yesterday because of flu, Bradley seemed virtually certain to start Steele Sunday. But Steele was still upset about being substituted for Wednesday and about front-office statements that he is through with the Dips at the end of the season.

The continued inactivity of Paul Cannell. The club's all-time leading scorer who says he wants desperately to play Sunday did not practice because of the groin pull he suffered Sunday in New York.Cannell said he will be ready to play Sunday. Bradley said he is not sure if Cannell will dress.

The unhappiness of Kenneth Mokgojoa. The South African winner has been disappointed about not starting all season and did not make the Los Angeles trip. The reason given: flu. Team sources say yesterday that Mokgojoa's "illness" was caused by the fact that he did not play against the Cosmos Sunday and felt that Bradley had lost confidence in him. Bradley said yesterday Mokgojoa "might" dress Sunday.

A general malaise following Wednesday's loss. The Dips have now lost three straight games and given up 16 goals in their last four games.

"We're down today," said defender Robert Iarusci as he watched his teammates practice shootout kicks. "There's a lot of things bothering people. It happens at the end of the season when everyone gets tense."

While Iarusci did not name anyone specifically, he admitted that the four defenders had felt let down by the midfield play Wednesday.

"We just weren't doing enough at midfield," he said. "You can't let them control the game out there like that. We know they have only two ways of attacking, through (Johan) Cruyff and with high passes to their tall forwards. We need to cut that kind of thing off sooner."

Viteskic, the Yugoslav midfielder, was the Dips' best player last season. This year, however, he missed seven weeks with a knee injury and has appeared tentative at times in the five games since his return.

"His next tackle will be his first," said Steele yesterday. "The problem with Sak is he never makes a mistake; he's perfect. The other guys make a mistake, they say it's a mistake. Not Sak. It's someone else's fault."

Viteskic said he has not been pleased with his play of late and said he had talked to Bradley about his problems with some teammates. "I will be ready Sunday," he said.

Steele also was promising to be ready Sunday after predicting Thursday that Bradley would not play him. But he was still incensed about Bradley's decision to replace him with a forward, Tony Crescitelli, after Los Angeles went ahead, 2-1, with 11 minutes left in the game.

"I still can't understand it," Steele said. "Why take me off? I wasn't playing badly. I was playing better than some of the bloody midfielders.

"It's been this way for awhile now. Something goes wrong, blame Steele or Cannell. And this thing about me being traded. I don't want to leave Washington. But when the season's over, that's probably it, I'm gone. That upsets me. I'm thinking about it all the time when I should just be thinking soccer."

Steele's best friend, Cannell, who did not dress for the game Wednesday and has not started since Los Angeles played here July 29, also was nonplused by his plunge in status.

"I can play Sunday," he said. "But I don't even know if I'll be in uniform. I hate to say it but this could be my last game in Washington. The fans here have been so great to me I would love to score, for them. For management, I couldn't care less. But the fans are magic as far as I'm concerned.