Maurice Lucas and Abdul Jeelani came off the Portland bench tonight and combined for 28 fourth-quarter points to lead the Trail Blazers to a shocking 109-99 come-from-behind victory over the fading Washington Bullets.

The Bullets played as well as they have all season for three quarters and seemingly had everything under control as they headed into the final quarter with a 13-point lead.

Then the Trail Blazers threw a full-court press at them and the Bullets panicked. Lucas and Jeelani scored almost at will and the Bullets had no clue whatsoever as to how to beat the press. they usually threw the ball away or dribbled into double teams and had it stolen.

Lucas scored 16 of his game-high 30 points in the fourth period and Jeelani had 12 of his 14 in the first eight minutes of the quarter.

During that deciding final quarter, Portland outscored the Bullets, 40-17.

The departure of Wes Unseld, who has a severe cold, helped start the Bullet collapse.

"Wes gets a stomach ache and gets dizzy they throw a press at us and we panic," said a perturbed Bullet coach, Dick Motta "We lost control. I'm so damn tired of this. We played hard enough to win and we should have if we just had enough sense to do what we're supposed to against a simple press.

"You can tolerate mistakes when you're going 100 percent, but when you make mistakes because you aren't mentally in the game, that hurts. We can't have that"

When they pressed, the Trail Blazers used a lineup of Kermit Washington, Lucas, Jeelani, rookie Jim Paxson and T. R. Dunn.

Lucas did what he wanted against Elvin Hayes, and Jeelani, a 6-foot-8 rookie from Wisconsin-Parkside, was working on Bob Dandridge.

Dandridge was playing for the first time after a 13-day layoff with a bad knee, foot and back.

The Portland victory evened the Trail Blazers' record at 21-21, but it was only their fifth victory in their last 20 games.

The Bullets lost their fourth in five and dipped five below .500, the lowest they have sunk this season.

At least the Bullets won't have much time to think about tonight's defeat. They play the defending National Basketball Association champion Seattle Supersonics Wednesday at the Kingdome (WDCA-TV, Channel 20 at 10:30 p.m.).

Things happened so quickly in the fourth period tonight that the Bullets hardly had a chance to realize what hit them.

With Jeelani hitting jump shots and with Lucas driving or hitting from outside, the Trail Blazers outscored the Bullets, 20-6, in the first five minutes of the quarter to take an 89-88 lead. A driving layup by Jeelani and an 18-footer by Lucas around a Hayes miss gave the Trail Blazers their first lead since the first quarter.

After a timeout, the Bullets regained their composure. Greg Ballard, who scored 18 points, made two straight long jumpers and Larry Wright scored on a baseline jumper while all Portland could come up with were two free throws by Washington.

Then the Portland press started taking its toll again. The Bullets turned the ball over twice and missed four straight shots as the Trail Blazers moved ahead.

Lucas scored on a 20-footer to cut the Bullet lead to 94-93 and then Jeelani scored on a layup after taking a pass from Lucas. Lucas then scored on another long jumper and, afte r a Dunn steal, slam dunked over Hayes as he was fouled. He made the free throw and Portland had a 100-94 lead with 1:44 left.

"They had to press to change the tempo of the game," said the Bullet Jim Cleamons, "and we didn't react. We let it rattle us. We swallowed it. jIt's just a recognition thing. It shouldn't have thrown us like that."

Hayes led the Bullets with 26 points and 11 rebounds, but he scored only two points in the final quarter.