CHICAGO – It's a good thing Judge Judy, better known as coach Avery Johnson, was on the scene Friday night.

Johnson had to be the arbiter of a disagreement between Devin Harris and Dirk Nowitzki early in the second half of the Mavericks' 100-92 preseason loss to Chicago at the United Center.

The players were on different pages on a defensive play that led to Nowitzki having to foul Luol Deng. Almost as soon as the whistle blew, Nowitzki started jawing at the point guard.

"He saw something he thought I should do and I saw it the other way," Harris said. "We got it worked out."

Harris said he probably wouldn't have gotten involved in the situation with Nowitzki last year. But he's trying to be more assertive as the starting point guard.

Shortly after the two argued, Johnson called them both to the sideline.

"I took care of it," he said. "I wanted to see if [Nowitzki] would let it go or show leadership. He showed leadership."

As Harris said, "He was Judge Judy and settled it."

Harris said both players had valid points. But the key to the situation was both players saw fit to voice their thoughts.

"It was really no big deal," Nowitzki said. "I saw something and we had a little argument. But it's no big deal.

"If we're going to go to the next level, we all have to work on communication. Maybe we have to work on how we say things, but at least we're communicating."

Defense is ahead: After 10 days of practices, the Mavericks' defense is further along than the offense, Johnson said.

Part of that is because they haven't found their shooting touch yet. Timing also has been slow to come.

But the defense has been solid, Johnson said.

"They're ahead because we've got more physical guys," he said.

Could that be the expanded weight program kicking in?

"They've given me a hard time about the weight training, especially when Dirk's little shot doesn't fall," Johnson said. "But they're getting stronger. He's saying, 'I'm Karl Malone.' He's never going to get there."

AP

The Bulls' Kirk Hinrich (left) and the Mavericks' Jerry Stackhouse battle for the ball during the first quarter.

Stepping up: J.J. Barea had a slow start to camp, but he put on a show in the first half against Chicago. He weaved through the Bulls' defense for 17 points and five assists, including one that led Nick Fazekas on a breakaway for a dunk.

"That was a pretty special pass," Johnson said.

Said Barea, "They had just scored a quick one, and I saw Nick down there, so I figured I might as well throw it."

Briefly: Josh Howard and Devin Harris were named co-captains for the game. It was the second game in a row Harris has been a captain. ... Jason Terry sat out the game. Jerry Stackhouse will sit tonight. ... Howard is off to a fast start in the preseason. He had 18 points in 15 minutes against the Bulls. "To see he and Deng going after it was pretty fun to watch," Johnson said. "Those are two of the young small forwards who are going to be around for a long time." ... The Mavericks met with Ronnie Nunn after their Friday morning shootaround. Nunn was going over the rules and situations that will be empahsized by referees this season. It's the same thing San Antonio went through Tuesday at American Airlines Center, except that they got veteran referee Steve Javie and his crew to go over things. Nunn is the NBA's director of officials.