DALLAS, April 9 (Ticker) -- The Portland Trail Blazers continue to display the lack of composure that haunts them near the end of every season.

Michael Finley scored 26 points and Nick Van Exel added 19 off the bench as the Dallas Mavericks remained atop the Midwest Division with a 108-96 win over Portland, which saw veterans Rasheed Wallace and Scottie Pippen ejected late.

The Blazers have acquired a reputation over the past few season for being an undisciplined team filled with difficult personalities. This season had been short on scandals and long on success as Portland has rebounded from a slow start to clinch a playoff berth.

But the Blazers, who have lost six of their last eight games, are starting to unravel again.

NBA TV highlights from Blazers-Mavs: 56k | 300k Nick Van Exel experienced plenty of contact from the Blazers on his way to a 21-point evening. Glenn James NBAE/Getty Images

"I would say that we let the referees control our game," Portland coach Maurice Cheeks said. "Sometimes as a game goes on, we let the referees play more than we are out there playing the game. I addressed that. We need to leave the referees alone and go out there and play because they take us out of our game for whatever reason. "

"It's got nothing to do with the officiating, it's all about us," Blazers guard Bonzi Wells said. "We've got to quit chirping on them as much as we do and just play the game the way it's supposed to be played. We've got to go out there and play and try to keep our mouths shut and stay into the game."

Wallace, who has a dubious history with officials, was ejected for arguing a non-call with less than a minute left in the third quarter. Pippen got into a scuffle with Van Exel with 2:11 remaining and threw a punch at the Mavs' point guard.

"(The Blazers) really think we're a bunch of (wimps), basically," Van Exel said. "Their team really just challenges your manhood and they've been going at us. I talk to them, that's really how they feel about us, that we're a bunch of soft, white boys and we can't get it done. So, we definitely showed them tonight."

Pippen had no comment about the incident but had plenty to say about the performance of his team.

"We're down at the bottom of the stick right now," he said. "We're not measuring up. We know where we stand with these teams. We've got a lot of work to do to be able to compete with them."

Dallas won for the fourth time in five games despite playing without injured forward Dirk Nowitzki, who is nursing a sprained ankle.

"We all knew we were going to miss Dirk at the start, but as the game went on you find a way to compete," Dallas guard Steve Nash said. "We were able to get by without him. Obviously we can only hold the fort down so long without our leading scorer."

The Mavs moved one game ahead of the San Antonio Spurs for first place in the Midwest Division.

Dallas led throughout the final three quarters but was clinging to an 89-86 lead after Wells drained a jumper with 5:17 remaining.

But Finley responded with a 3-pointer 15 seconds later and, after a basket by the Blazers' Shawn Kemp, he nailed another shot from beyond the arc for a 95-88 edge with 4:19 to go.

Raef LaFrentz extended the lead with a fast-break at 2:39 and sealed the victory with a jumper 40 seconds later.

LaFrentz finished with 15 points, 11 rebounds and five blocks and Nash collected 14 points and nine assists for Dallas, which shot 46 percent (36-of-79) from the floor and made 11-of-31 3-pointers.

Wells led the Blazers with 26 points and Damon Stoudamire and Wallace added 16 apiece. Dale Davis scored 12 points and Pippen had 10 and eight rebounds as Portland remained two games behind fifth-place Minnesota in the Western Conference.

The Blazers shot just 42 percent (36-of-84) and made only 3-of-17 3-pointers.