The 29.1 percent field-goal shooting — including 22.2 percent in the first half, when the game still held a semblance of competitiveness — was just a symptom of a bigger problem.

The Bulls, known for their selflessness, toughness and determination, have become vulnerable.

This has nothing to do with last week’s trade deadline — or the comments made last Thursday by Derrick Rose’s older brother regarding the team’s inactivity, which were supported by at least one player — or even their injured superstar’s absence.

What’s ailing the Bulls right now is the inability to consistently simply will their way to wins or at least close games against certain types of teams, the ones that play focused, possess superior athletes, execute on both ends and refuse to be cowed by the hard-nosed squad’s usual persistence.

“We’ve got enough. We have to do our jobs. Do our jobs. We’ve shown when we do that, we’re capable of beating anyone. We have to be mentally tougher, we have to be stronger. When you face a little bit of adversity — whatever — if you’re short-handed, you have to dig down and get the job done,” a clearly disappointed Tom Thibodeau explained. “We just had a stretch where we had 10 out of our last 12 on the road, but our road doesn’t get any easier. We go home and we’ve got to play a lot tougher. Our level of intensity has to be much higher. We’ve got to get that part right. We’ve got to get it right quickly.”