Kevin Grevey scored 29 points and rookie center Rick Mahorn added 15 and 16 rebounds last night as the Washington Bullets ended their exhibition season with a 121-111 victory over the New York Knicks in the second game on a Capital Center doubleheader.

The Philadelphia 76ers downed the New Jersey Nets, 90-86, in the first game.

Last night's victory gave the Bullets a 3-5 exhibition season record. The Knicks, 2-5 in the preseason, have one game left before the regular season begins.

The Knicks were led by Campy Russell's 22 points. Ray Williams added 20.

Both teams were shorthanded. The Knicks played without their two allstars, center Bill Cartwright, who has a bad back, and guard Michael Ray Richardson, who has a sprained ankle. The Bullets were without Mitch Kupchak, who has a sore elbow, and Kelvin Porter, who missed the game because of an injured knee.

The Bullets jumped to an early lead, but never could put the Knicks away. Each time it appeared the game was about to be broken open, the New Yorkers would rally.

The Knicks missed 14 of their last 16 shots of the first half and the Bullets held a 70-56 lead at intermission.

Williams sparked the Knicks in the third period and they closed to 82-77 with four minutes left in the quarter. But rookie Wes Matthews, who had 10 assists and scored eight points, sparked a bullet rally that hiked the lead back to 11.

Mike Woodson, the Knick's No. 1 draft choice, led a fourth-quarter comeback that had the Bullets scrambling. Woodson's 10-footer, followed by his baseline jumper, cut the lead to a point at 97-96 with 7:40 to play. But Mahorn drilled a 10-footer and Greg Ballard added a fast break layup to get the Bullets' lead back to five points and the Knicks never really threatened thereafter.

Grevey, who has scored at least 20 points in each of the last three games, made 11 of 17 shots last night and had seven assists and three steals.

Bob Dandridge also played a strong game for the Bullets as he made seven of eight shots and scored 18 points. He also had committed seven turnovers.

John Williamson, Grevey's backup, made seven of 11 shots and had a surprising four assists. With Porter sidelined, Williamson saw some action as the playmaking guard.

The Knicks struggled most of the game because of problems in the middle. With Cartwright on the bench in street clothes, that left Marvin Webster as the only Knick center. He played well, but picked up four fouls in the first quarter and played only 28 minutes, with 13 points, seven rebounds and four assists. He eventually fouled out, as did the Knick's only other true big man, Larry Demic.