So much ugliness was attached to tonight’s game, only some of it connected to good defense. Both teams were clearly crawling for the five-day vacation.

The Celtics were treated to another endurance test, with the result a grinding 71-69 victory.

As evidenced by the nights of everyone from Paul Pierce, Jeff Green and Avery Bradley, who shot a combined 8-for-32, this was the kind of basketball probably witnessed by the father of the game, Dr. James Naismith.

The Celtics, who survived an 11-point second quarter followed by an eight-point third, shot 36.8 percent to Chicago’s 36.5.

But they also, curiously, tied the season series at a final 2-2.