"Perfect" is the way Coach Gene Shue put it, and it would be hard to describe it better.

After falling behind by 13 points in tonight's first half, and still trailing by a point with 4:55 to play, the Washington Bullets pulled away from the Dallas Mavericks with the scoring of Greg Ballard and Dave Batton, the rebounding of Rick Mahorn and a clinging defense to win, 115-105. Their sixth victory in the last seven games evened the Bullets' record at 9-9.

"We had an outstanding fourth quarter," said Shue. "We took the momentum away from them and everything worked perfectly."

The Bullets outscored the Mavericks, 37-22, in the final period, shooting 74 percent. Ballard, who had 24 points, scored 11 in the fourth quarter. Jeff Ruland, who did not play much of that period, and Frank Johnson each scored 18 and Kevin Grevey had 16, making five of six shots.

Johnson constantly infiltrated the tiring Mavericks' defense and passed to the forwards cutting off picks in the low posts. He had 12 assists.

Rick Mahorn, who had 18 rebounds, his most as a pro, said he had been surprised by Dallas' expansion team.

"After playing them last year, the Mavericks are a surprise," said Mahorn. "Mark Aguirre is amazing from inside and outside.

"We played beautifully there at the end," he said. "In the first half, the ball just wouldn't drop. We just kept at it. Ruland was just a little offbalance tonight, but he'll get it back. We made up for it. Frank and Greg and Dave went to work . . . and that turned it around."

Despite Aguirre's game-high 30 points, Shue credited Mahorn with keeping Aguirre and forward Jay Vincent from putting the game out of reach when that was a possibility.

"Rick had another outstanding game," said Shue. "He is excellent on defense and we used him on either Vincent or Aguirre, whichever got hot."

Except for a couple of periods in the first half, when they had trouble scoring, the Bullets played fairly consistently. But two scoring bursts in the last half demoralized, and finally defeated, the Mavericks.

After steadily cutting into Dallas' 10 point half-time lead, the Bullets closed with a rush at the beginning of the fourth quarter. Trailing, 83-78, Batton opened the Washington scoring with a 17-foot jumper.

Vincent was called for traveling, a violation that plagued both teams all game, and Grevey made two free throws after he was fouled under the basket to put the Bullets within one point. Again they got a defensive rebound and Mahorn finessed an eight-foot jumper from the side.

Ballard stole the ball from Aguirre and got a dunk that put the Bullets ahead, 86-83.

The Mavericks rallied, led again by Aguirre. Shue, who picked up a technical earlier in the game, substituted Don Collins for Grevey and Mahorn for Ruland, and with a faster team the Bullets broke away.

The second, and decisive, surge started 4:46 into the fourth period. On Ballard's sharp pass to the cutting Collins, the Bullets went ahead to stay, 97-96. The Mavericks could score only nine more points while the Bullets scored 18 from inside, outside and the free throw line.

"There's no hiding it," Aguirre said. "We just didn't execute. We didn't play heady basketball . . . If we had worked and taken the open shot, we would have buried them."

But they didn't. The Mavericks had seven turnovers in the final quarter while the Bullets, after 14 through three periods, lost the ball only once.

And that's almost perfect.