TLANTA - There are some mistakes that make coaches cringe (turnovers), and some that make them yell (failure to crash the boards).

While coach Jim O'Brien has had occasion to exhort the Celtics to rebound better, he rarely has had reason to recoil about balls being thrown away or possessions being wasted. The Celtics rank second in the NBA for fewest turnovers per game (12.1) and second in assists-to-turnover ratio (1.94). Last night, even in a 112-103 defeat, they had 11 turnovers to the Hawks' 18.

The Celtics' ability to handle the ball with care has produced what you might call a ''trickle up'' effect. They currently rank seventh in the league in points with an average of 100.8.