In the only two starts he has made in his rookie season, Copeland has produced 64 points.
New York wrapped up the second-best record in the Eastern Conference (54-28) and will meet Boston to open the playoffs.
The Knicks' Carmelo Anthony rested a bruised left shoulder, but still won the NBA scoring title with a per-game average of 28.7. He took part in 67 regular-season games and scored 1,923 points.
New York led by as many as 17 points with less than 4 minutes to play before the Hawks put on a late spurt. Atlanta, however, could come no closer than the final score.
Atlanta finished as the No. 6 seed in the East with a 44-38 record and will face Indiana to start the playoffs. Mike Scott paced the Hawks with 23 points.