"We tried to run them out of the gym in the first half, but it backfired," Arenas said.
Nowitzki scored seven of his 30 points in a game-turning spurt that ended the third quarter and had 14 rebounds for the Mavericks, who stretched their NBA-best winning streak to seven with a 107-80 victory Tuesday night.
Dallas hasn't lost since following its trip to the NBA Finals by starting 0-4 for the first time.
"I think we were just trying to find ourselves a little bit," said reserve Austin Croshere, who had 14 points and was one of six Mavericks newcomers who played. "Early, we were waiting for things to happen, and now we're making things happen."
Arenas, who had 45 points in Washington's last game, already had 26 against the Mavs when he made a tiebreaking 3-pointer with 9:29 left in the third quarter.
Then the Wizards went cold, missing 10 straight shots. By the time DeShawn Stevenson drove for a basket in the opening minute of the fourth quarter, the Wizards were down by 12 points.
And Arenas scored only three more points -- all free throws -- and struggled shooting. On consecutive shots during the Dallas streak, he had an offensive foul and hit the side of the backboard with a 12-footer.
After Arenas made his last field goal, Nowitzki responded with one of his own 3-pointer to tie the game at 58. That started a 21-6 run over the remainder of the third quarter that put the Mavericks firmly in control.
Washington hasn't won any of its first five road games, the latest it has gone this deep in the season without a road victory since 1999-00. The Wizards play in Houston on Wednesday night.
With Dallas playing its fourth game in five days, coach Eddie Jordan thought the Wizards "could have the energy and outlast them for 48 minutes."
They barely made it past halftime.
Jason Terry and Devin Harris both had 18 points for the Mavericks, and watched the final 3:46 with Nowitzki after Johnson cleared his bench. Anthony Johnson had 11 points in 17 minutes, while DeSagana Diop had 13 rebounds.
Caron Butler had 12 points and 11 rebounds, and is the only Washington player with at least 10 points in every game this season.
Three days after scoring 45 against Cleveland, Arenas looked like he was on way to consecutive 40-point games for only the second time. Plus, he had a 43-point game in Dallas two seasons ago.
Arenas made two baskets in the first minute of the game, prompting a quick timeout from Johnson. It didn't stop the Wizards' All-Star, who had 15 points by the end of the first quarter, when the Wizards led 30-21.
"He got going early. He was the aggressor," Jordan said. "We wanted him to be aggressive. That was the only reason we were in it."
Arenas hit two free throws with 6:13 left in the game, his last points and the only ones he scored after making a free throw with 7:33 remaining in the third quarter.
The Mavericks started the second quarter with a 10-0 run, going ahead on Greg Buckner's 3-pointer. After that, the margin was never larger than three points until Nowitzki's 14-foot fadeaway jumper made it 64-60 early in Dallas' impressive surge.
- Johnson said F Josh Howard , who has missed eight games since spraining his left ankle Nov. 6, will resume practice in the next few days and could be back in the starting lineup by this weekend.
- Jerry Stackhouse missed his last 12 shots after making his first two to give Dallas an early 9-4 lead.
- The 30 points by Washington were the most the Mavs have allowed in a first quarter this season. Dallas' 21 points were the fewest given up by the Wizards in an opening quarter.
- Devean George missed his second straight game for Dallas because of a hyperextended right knee.