Forty-three games into the season and the Bulls are still struggling with focusing on a consistent basis, specifically against lower-tiered teams.

That's according to center Robin Lopez, one of the few Bulls who did show up in their 99-98 loss to the Dallas Mavericks on Tuesday night.

Though buzz words such as energy, effort and consistency can be cliche for a team over the course of an 82-game season, where lulls are bound to occur at one point or another, question marks regarding those traits have followed them all year.

Tuesday night marked the Bulls' 12th loss against a team with a record below .500. They are the only of the current 16 playoff teams with a losing record (9-12) against sub-.500 teams. That .428 win percentage is far worse than the .703 win percentage the remaining 15 playoff teams have against such opponents.

"I really think it's an issue of focus," said Lopez, who had 21 points and five rebounds in 36 minutes against the Mavericks. "I think against the good teams we've displayed that focus. We're a little more keen because we're afraid of losing to good teams. There are moments I think where we take certain situations for granted and we have mental lapses.

"I'm not going to go out there and question anybody's effort," he said. "I think we're all busting our asses. But focus is something a little bit different. That's something all of us can be a little bit more consistent with."

Those inconsistencies that dropped the Bulls (21-22) below .500 for the fourth time this season are more frustrating because of their continued successes against the league's elite teams. Just 43 games in, the Bulls have wins over Cleveland (twice), Toronto, San Antonio, Memphis, Utah and Boston.

"We're afraid of losing to good teams in a good way," Lopez clarified. "I think it's a good fear. You go in against the Cavs or somebody, the champs, and you have that fear in your gut. That's a natural instinct. That's a good fear to have because it drives you to stay focused and to be prepared.

"I don't think we have that fear or level of respect at times for other (lesser) opponents."

Focus may be a factor in the Bulls' recent woes against bottom feeders, but so too has production from the second unit. A year-long issue reared itself on Tuesday when the reserves lost the lead in the second quarter that allowed Dallas to take a lead into halftime. The reserves shot 8-for-23 and had almost as many personal fouls (14) as they did rebounds (16) in 90 combined minutes. Though Doug McDermott tied the game at 96-96 in the final minute, the second-quarter struggles from than unit loomed large in a game that was decided in the final seconds.

The bench has been a bit of a revolving door in the past few weeks. With both Denzel Valentine and Nikola Mirotic battling illnesses, and Taj Gibson missing Tuesday's contest with a sprained ankle - he'll play Friday in Atlanta - Hoiberg has had to adjust on the fly, and playing time has been sporadic because of it.

"We do have so many young guys on that bench, and all of them at some point over the course of the year have given us good minutes," Hoiberg said. "You've just got to try to find the right combinations to put out there. It's something that we'll continue to juggle until we find the right group and the right mix out there coming off the bench."

Still, little victories like the Bulls fighting back in the third quarter from 13 down and eventually take the lead early in the fourth quarter proved to Hoiberg that there's enough talent on the team to show it on a more consistent basis. With seven games against teams with winning records before the All-Star break, the Bulls will need to show that effort more frequently as they fight for positioning at the bottom of the Eastern Conference playoff race.

"Keep working on it, keep harping on what's important out there. And again, (in the) second half we did it. I told our guys they screwed up. They showed me that they can do it," Hoiberg said. "It's 48 minutes, it's consistency. And we'll keep working on it."