The team were beaten 103-102 by the New York Knicks in pre-season last night and had a chance to claim the win in the final seconds of the game, but Chris Babb's effort was blocked.
The head coach told ESPN: "Chris Babb has been one of the best workers, had one of the best attitudes and been one of the best teammates in there from day one.
"So, not a shock at all when he went in and did what he did. We have been huge fans of his since he walked in the building. That was fun to be a part of. That's the way we need to play.
"I thought we competed awfully hard at times, and at times I thought they were better than us. We've got to be more consistent through 48 minutes, and that's what the pre-season's for."
The Celtics face the Philadelphia 76ers in their next pre-season game tomorrow.