EW YORK - The Celtics' ability to blank big man Marcus Camby in the final quarter was key to their 90-81 victory over the Knicks last night. Camby failed to take a shot and had only one rebound in the final 13 minutes of play.

''We were making a fundamental mistake to let Camby score,'' Celtics coach Jim O'Brien said. ''We did not follow the game plan perfectly but once we did, we eliminated Camby. You can't roam off Camby and [ Kurt] Thomas in the middle.''