As good as it's been for his team over the first 19 games of the season, Celtics coach Jim O'Brien believes things can get even better. After conducting a light practice yesterday at The Sports Authority Center in Waltham, O'Brien said he still views the Celtics as a work in progress.

``I've been really pleased that we've been in every basketball game,'' said O'Brien, whose team is 12-7 following its 102-93 overtime victory against the Knicks on Tuesday night in New York. ``At key times, even when it would appear the game is out of hand, we've been able to put ourselves in a position to win. It's just nice to see that our guys have really stepped up in a lot of cases with the game on the line.''