Ellis started his Dallas career with 32 points, Nowitzki scored 24 and the Mavericks spoiled Mike Budenholzer's coaching debut with a 118-109 victory over the Atlanta Hawks on Wednesday night.
The Mavericks went 7 of 8 from 3-point range in the fourth quarter to pull away, including two in a row from Nowitzki followed by one from Ellis for a 118-102 lead with 1:18 remaining.
"The way he played in the second half was fantastic," Mavericks coach Rick Carlisle said of Ellis, who was an elite scorer at Golden State before his shooting percentages dropped off the past two seasons. "He played a terrific game. Dirk played a terrific game as well."
Jeff Teague led Atlanta with 24 in Budenholzer's first game, which came against a familiar opponent since he was a longtime assistant to Gregg Popovich in San Antonio.
"Give Dallas a lot of credit," Budenholzer said. "They played really well for long stretches. A lot longer than our stretches."
Ellis, who signed a three-year deal as a free agent, joined the Mavericks with questions about his efficiency on offence. He answered those concerns for one night at least, going 11 of 17 from the field with eight assists. The only downside was seven turnovers, and Dallas had 20 as a team.
"Coach showed me some clips about how teams were playing me," Ellis said. "When I would get in the lane, I was more looking for a pass. I wanted to be one, two dribbles and put it up. Then if they played me, I could cross over and get the ball to somebody else."
Nowitzki finished 8 of 14, including 4 of 6 from beyond the arc, after missing last year's opener and the next 26 games following right knee surgery.
The early moments of the second half offered a glimpse of how these two scorers will feed off each other. Nowitzki opened the scoring with a jumper off an assist from Ellis in the pick-and-roll, then Ellis came around a Nowitzki pick for a 20-footer.
The next Dallas bucket was a jumper from Ellis, with an assist from Nowitzki.
"Monta is sensational in those pick-and-rolls coming off looking aggressive to score or if he doesn't have it he's finding the open shooters and that was fantastic," Nowitzki said.
The Mavericks opened with a win over an Eastern Conference playoff qualifier from last season after they missed the post-season in the West for the first time since Nowitzki's second season in 2000.
Until Nowitzki and Ellis put it away, the Hawks stayed close in their first game without Josh Smith, who went to Detroit in free agency.
"We played hard and competed," Teague said. "We were getting used to each other. We've got some time to do that."
Jose Calderon, Ellis' new backcourt mate and another of the nine new faces in Dallas, struggled offensively until the fourth quarter, when his first field goal was a 3-pointer that answered one on the other end by Carroll to put Dallas up 107-97.
Calderon had five points and a game-high 11 assists, including one on an alley-oop dunk by Vince Carter that started a 17-2 run to put Dallas ahead 84-72 late in the third quarter.
Carter, who had 21 points, added a 3-pointer from several feet behind the arc later in the run to extend his streak to 26 games with at least one from long range dating to last season.
Cartier Martin, who had 17 points, hit a 3-pointer to pull Atlanta within 84-76 going in the fourth quarter.
The Hawks got as close as three early in the fourth, but Nowitzki hit a 3-pointer and Ellis answered a bucket by Millsap to start 7-0 run that put the Mavericks up 99-88.
Nowitzki looked comfortable right away, making his first three shots and getting a couple of assists early before finishing the first half with 13 points.