Hubie Brown has spent the last two seasons trying to instill his vast basketball knowledge in the minds of his Atlanta Hawks.

He prepares them for games with computer-like precision, he dictates almost every move they make and he continually reminds them they can win only if they do not question his theories.

There is just one area in which he can't help the Hawks. He can't make them immune to playoff pressure. And this could lead to his club's downfall in the Eastern Conference semifinal series against Washington that resumes at the Omni Sunday (1:30 p.m. WDVA-TV-9).

The opening three games of the round all have been decided by lopsided scoring spurts early in the fourth quarters. Twice the Bullets have managed to finish on top, giving them a 2-1 lead in the best-of-serven showdown.

Now Brown says the rest of the series will be determined "by who folds first"

He says, "Some will say we are too young and that their 504 playoff games to our 33 is showing. All I know is that when both teams are so well prepared, it comes down to experience. They know what it takes to win in these games."

For Atlanta to win game four, the Hawks will have to witstand what Bullet Coach Dick Motta says "is the most pressure they've felt yet. It's going to be brutal."

If the Hawks lose, they will be in a horrible position, trailing 3-1, with the next game scheduled Tuesday night in Washington. If they win, both Motta and Brown Feel it will take seven games to decide which team advances to the conference finals.

"It's a cliche but we've been here before and Atlanta hasn't," Motta said. "It makes a difference. We found out last season what it took to win on the road in the playoffs and how to overcome crowd noise and the rest.

"Shots start getting harder in the fourt period. Things tighten up. Suddenly they mean a lot more. Everything you talk about kind of loosens up and the natural instincts take over. That's when it's nice to have veterans like Elvin (Hayes), Bobby (Dandridge) and Wes (Unseld)."

Against this experienced Washington front court, which has 31 years' total NBA experience, the Hawks have to counter with John Drew (four years), Steve Hawes (four) or Tree Rollins (two) and Dan Roundfield (three). And Drew, the club's leading scorer, is perhaps Atlanta's most unreliable pressure shooter.

"We have to win within a team concept," Brown Said. "We have to excel as a team. In our losses in the series, our patience has been lacking. If we play them one on one, we come up short.

"It got to where our offense was like a pinball machine. You know, it was bouncing around, out of control but we weren't scoring.

"If things get into power game in the fourth period, their strength vs. ours, it's their game.They'll win. It's that simple."

In their one victory, the Hawks, shot an incredible 73 percent in the fourth quarter, thanks in part to a good running attack.

But in their losses, they have fired away at 21 percent and 31 percent during those final 12 minutes. Drew had eight points in the last period in game two, but only four in the other contests.

"We hit bottom Friday night," Brown said. "It was only the second time at home this year that we've shot under 40 percent for the game. Toss in 20 turnovers and the fact that our starters made only 22 of 64 attempts and committed 15 turnovers. Well, we just can't play that way.

"It's not that we aren't getting our opportunities. We had 31 transition plays and got only 11 baskets. To win, we have to score in the open floor. That's how we have won for two years. We just can't set up every time against them and be successful, unless we have excellent execution."

Ironically, the Bullets likewise feel they must play a more free-flowing game. Yet neither team has been able to break out of the slow-down, set-it-up tempo other than in those crucial fourth periods.

"It would be nice," said Dandridge, "to break out on top of them early instead of always coming down to the fourt period.

"But that is how it looks like they want it. If they keep it close until then, I guess they feel they have a shot at us."

Washington still is playing well below its capabilities. It has produced just two quarters of quality basketball; otherwise the club has shot poorly and rebounded dreadfully. Only increasingly tougher defense has kept the Bullets competitive enough to stay even with the Hawks.

There were signs Friday night that they were snapping out of their inconsistency. Once Kevin Grevey began hitting outside late in the third period, the rest of the offense opened up. The Bullets began fast-breaking and moving the ball with authority against Atlanta's sagging zone defense.

Motta had been hoping that one of his outside shooters would snap out of his slump and provide the team with what he calls 'a third hot hand" to go along with Dandridge and Hayes. Unless Washington has good perimeter marksmanship, Atlanta can concentrate almost totally on swarming the front-court players, cutting off the Bullet's main offensive plays.

"Their defense is designed to stop you inside and force you to win from the outside first," Motta said. "A few hot shooters would loosen up a lot of things."

Grevey who usually plays well against Atlanta, had made 10 baskets going into the game, but only a couple were from the outside. And Charles Johnson, his replacement, is now just four of 17 in the series.

"I'd like to see up play one strong, consistent game," said Motta. "That's what we need right now."