The Washington Bullets couldn't score a point in the final 3 1/2 minutes tonight and lost to the Atlanta Hawks for the second time this National Basketball Association preseason, 108-100.

After two Bob Dandridge free throws put the Bullets on top, 100-98, the Hawks reeled off the game's final 10 points to come away with the victory in the first game of a Madison Square Garden doubleheader.

The host Knicks defeated the Boston Celtics, 113-107, in the second game.

John Drew, who led the Hawks with 21 points, had four of the final 10.

The Bullets were plagued by cold shooting, but stayed alive with an outstanding third period in which they outscored the Hawks, 34-17, to turn a 60-49 halftime deficit into an 83-77 advantage going into the final 12 minutes.

Greg Ballard and Kevin Grevey, utilizing crunching picks by Wes Unseld and Elvin Hayes and fine passing by Kevin Porter and Wes Matthews, combined for 24 points in the quarter, 13 by Ballard and 11 by Grevey.

Ballard led the Bullets with 19 points, while Grevey and Matthews finished with 15 each.

The Bullets shot a horrid 27 percent from the field in the first half and 36 percent for the game. The coldest shooters were the shooting guards, Grevey and John Williamson. Grevey went five for 17 and Williamson two for 13.

"There were some encouraging things out there, especially in the third quarter," Coach Gene Shue said. "We overplayed their guards well and forced their big men to bring the ball up court. I wasn't at all disappointed in our defense tonight.Offensively, we're not . . . smooth; let's put it that way. It'll develop, though.

"As we get closer to the regular season, the players who are supposed to score will get the shots. We're still really in the learning process and I'm a patient person. I know things will work out."

Ballard, who made eight of 14 shots and converted the Bullets' first three-point shot of the exhibition season agreed that the Bullets played good defense and said that the offense will materialize.

"Defense is what we've been working on and it's paying off," he said, "and the defense helps the offense. We all know the offense will come."

Rookie Don Collins, who signed with the Hawks last week, scored 15 first-half points and Atlanta appeared to have the game under control with an 11-point halftime lead.

Atlanta Coach Hubie Brown had a substitution pattern that he stuck to which meant he played his reserve against the Bullet regulars much of the third period when the Bullets took the lead.

With six minutes to play and the Hawks trailing, 94-93, Brown brought back Dan Roundfield and Steve Hawe and the Bullets couldn't keep up.

After Dandridge's free throws, the Bullets missed their last six shots. Atlanta then scored on driving layups by Collins and Drew, an 18-footer by Eddie Johnson and on four free throws, two by Drew and two by Roundfield.