O.J. Mayo scored 20 points to lead six Dallas players in double figures and the Mavericks, despite the absence of Nowitzki, dominated the fourth quarter in a 109-99 victory.
Darren Collison added 19 points and Vince Carter 17 for the Mavericks, minus Nowitzki for the second game in as many nights because of a sore right hip.
Shannon Brown scored 20 and Goran Dragic added 19 points, nine assists and eight rebounds for the Suns, 0-3 against Dallas this season and losers of 11 of the last 12 in the series. Two of the Mavericks' wins this season over the Suns came without Nowitzki.
Dallas had to shake off Thursday night's tough loss at Golden State.
"In this league, you have to forget about it and move on to the next game," Collison said. "So we forgot about it just in time and we wanted to make sure we closed this one out, and we did."
After 12 first-half turnovers, Dallas had three in the second half.
"Guys did a much better job," coach Rick Carlisle said. "Our execution was better, our defense was better, our rebounding was better so we were able to finally get a lead and build on it."
Shawn Marion scored eight of his 14 points in the fourth quarter for Dallas.
The Suns lost at home for the first time in four games since interim coach Lindsey Hunter took over from the fired Alvin Gentry.
"We are still young in this process and you kind of expect things like that to happen," Hunter said of his team's inability to get fourth-quarter stops. "I know what lies ahead of us and I know how hard it is, just trying to get everybody collectively as a group to understand that you have to do it together."
After scoring a season-high 27 points in Wednesday night's win over the Lakers and averaging 18.2 points per game since Hunter took over, the Suns' Michael Beasley was 2 for 13 shooting for four points.
"I shot the ball great tonight," Beasley insisted.
But he didn't make many of them.
"I got the shots I wanted," he said. "The ball just didn't fall. That's it."
The Mavericks trailed most of the night before Carter's 3-pointer put them up for good, 84-81, with 8:51 to play. The basket was part of a 12-4 run that gave Dallas a 92-85 lead on Jae Crowder's 3 with 6 minutes to go.
Phoenix never got closer than five again.
The fourth quarter collapse was in contrast to the Suns' emotional, come-from-behind victory over the Los Angeles Lakers two nights earlier.
"Our intensity was not the same like last game," Dragic said. "We were not engaged in defense."
Dallas' only lead of the first half was at 2-0 but the Suns never were up by more than seven in the first two quarters and it was tied at 54 at the break.
Dragic had 10 points, four rebounds and four assists in the first quarter, with the Suns holding a 31-29 lead. Brown opened the second quarter with a pair of 21-footers to make it 35-29, then capped an 11-4 run with a 3-pointer to put Phoenix up 40-33 with 9:10 left in the half.
The Mavericks caught the Suns with a 15-8 surge, tying it at 50 on Mayo's 3-pointer 2:16 before the break.
The Mavs went nearly 4 minutes without a point as the Suns scored 11 straight to go up 71-61 on Marcin Gortat's layup with an assist from Dragic with 4:45 left in the third quarter. But Dallas responded with a 13-2 run to take the lead for just the third time of the night, 74-73, on Brandan Wright's inside basket with 1:12 left in the period. Brown's basket 20 seconds later put Phoenix up 75-74 entering the fourth.
NOTES: The Suns play seven of their next eight on the road, where they are 4-19, second-worst in the NBA (Washington is 3-20). ... For the second time in three games, Hunter used rookie Kendall Marshall as the backup point guard instead of Sebastian Telfair. ... Dallas is 13-16 without Nowitzki, 7-11 with him. ... The teams don't meet again until April 10 in Dallas, where the Mavs can sweep the season series. ... Dragic has one career triple-double. ... The Suns are 3-3 since Hunter took over.