Mavericks forward Dirk Nowitzki shoots over Wizards defender Trevor Booker. Nowitzki finished with 27 points. (Tony Gutierrez/AP)

The Washington Wizards are unsure if the team that took the floor against the Dallas Mavericks on Tuesday will resemble the squad that takes on the New Orleans Hornets after Thursday’s trade deadline. But if little to nothing changes with the roster, Coach Randy Wittman made it clear before the team arrived in Dallas that the Wizards would have to make a more solid commitment to playing defense for a full 48 minutes if they are ever going to improve as a team.

“We can talk about it all we want,” Wittman said. “It’s just a matter of understanding that and going out and doing that.”

Wittman is still waiting for the Wizards’ play to support the talk. Despite NBA Finals MVP Dirk Nowitzki missing significant time because of foul trouble, the Wizards were unable to fend off the Mavericks’ ancillary pieces down the stretch and lost, 107-98, at American Airlines Center.

Trevor Booker, doing his best to make Nowitzki work on offense and defense, finished with a team-high 20 points and 12 rebounds. John Wall also had a double-double with 18 points and 12 assists. But the Wizards were unable to contain reserves Jason Terry and Rodrigue Beaubois, who combined to score 43 off the bench to hand the Wizards (9-32) their sixth consecutive road loss. Washington dropped to 3-16 away from Verizon Center this season.

“It’s the NBA, it’s a lot of great players and at different times they can step up,” said Andray Blatche, who scored 11 points off the bench while being mentioned in trade speculation. “That’s what their guys did when Dirk came out of the game. We’ve got to find ways to not let players that don’t usually do that do that to us. That happens to us a lot.”

The Mavericks took a 68-56 lead with about 81 / 2 minutes left in the third quarter thanks to a four-point possession. Nowitzki was fouled as he hit a turnaround jumper and Jordan Crawford received a technical foul for complaining about not getting a foul call on the other end. Nowitzki then hit two free throws, but the Wizards responded with a 10-0 run to get within two.

The Wizards cranked it up on the defensive end, forcing the Mavericks (24-20) to miss 11 of their first 14 shots in the third period. Booker helped by attacking the boards and the basket, getting Nowitzki in foul trouble in the process. Nowitzki scored just seven of his game-high 27 points in the second half, when he was limited to just more than 10 minutes.

“Dirk was hitting some tough shots in the first half,” Booker said. Wittman “told me not to get down on myself and he told the whole team to keep fighting and that’s what we did in the third quarter. We just tried to attack him.”

Wall had a driving dunk to bring the Wizards within 75-72, but the Mavericks responded with a 17-7 run over the next six minutes. After Terry made a pull-up jumper in transition to give the Mavericks an 81-73 lead, Blatche tried to take advantage of what appeared to be a mismatch with the 6-foot-2 Beaubois. Blatche backed down Beaubois but when he went up for a short jumper in the lane, reserve center Ian Mahinmi swatted the shot in the opposite direction. Terry grabbed the ball, darted up the court and missed a layup, but Beaubois came from behind to tip in the shot.

A night after San Antonio’s Tony Parker had his way with the Wizards, his fellow Frenchman Beaubois managed to come off the bench and completely turn around the game for the Mavericks. He scored 19 points and gave the Wizards fits in a variety of ways. He drove inside, got Wall to bite on a jump fake, then buried a jumper. He later flew inside to tip in another Terry miss that gave the Mavericks a 91-79 lead in the fourth quarter.

The Wizards’ Nick Young had 15 points off the bench and provided a huge highlight as he soared over Mahinmi and dunked in the second half. But he also had a lowlight in the first period, when he raced up the floor for what he thought would be an easy fast-break layup. As he elevated to shoot, Beaubois snatched the ball away and recovered it before going out of bounds.

Young made back-to-back jumpers to give the Wizards a 40-38 lead near the end of the second period, but the Mavericks closed out the second period in commanding fashion, outscoring them 22-11 over the final 6 minutes 34 seconds. The Wizards had several defensive lapses during the run, with Wall letting Terry get past him for a layup, JaVale McGee letting former Wizard Brendan Haywood get open for a dunk and Young leaving Shawn Marion to catch an alley-oop dunk. And finally, the Wizards got lost in a series of bad rotations that resulted in Nowitzki drilling an open jumper that gave the Mavericks a 10-point lead.

Wittman was still pleased with how his team battled back.

“We came here and I thought we fought them tooth and nail,” Wittman said. “Against good teams like this, your margin for error of us, being what we are as a young team, is small. We’ve just got to keep fighting like that, and keep improving. Making steps in the improvement defensively we need to make.”