"My teammates were looking for me," Marion said. "I've been able to do a lot of different things on the floor."
Marion, who entered with five 3-pointers all season, went 4 of 6 from behind the arc and 11 for 20 from the field.
Marion is averaging 19.3 points over his last four games, helping make up for the loss of Nowitzki (17.5 points per game) and Carter (9.5 ppg).
"Shawn was great," Mavericks coach Rick Carlisle said. "A lot of plays he made were very timely. ... We needed someone to step up."
Ian Mahinmi chipped in with 17 points and nine rebounds for the defending NBA champion Mavericks (11-7), who returned home from a 2-2 road trip.
"This was one of those games when we felt we needed that spark," Mahinmi said. "When you come off the bench, you bring that energy, and we got the starters going again."
Nowitzki missed his second game in what has been projected as a four-game stretch to work on his conditioning and allow his sore right knee to improve.
Carter sat out his fourth consecutive game with a sprained left foot.
Carlisle said Nowitzki went through two conditioning sessions on Monday. The MVP of last year's NBA Finals will be monitored as the week goes on to determine his progress.
Carlisle said the German star could miss more than four games depending on how much improvement he shows.
"There's some conditioning and some things with the knee that need to be resolved," Carlisle said.
Grant Hill scored a season-high 19 points for Phoenix and Marcin Gortat had 19 points and 17 rebounds, his eighth consecutive double-double. Shannon Brown added 14 points for the Suns, who have lost six of eight.
Phoenix has dropped its last nine games at Dallas.
Dallas continues to play tough defense, holding an opponent under 100 points in its 15th straight game to extend its franchise record.
Marion's nine points sparked a 10-2 third-quarter run. Marion, who had 14 points in the third quarter, converted a three-point play, then hit consecutive 3-pointers to give Dallas a 70-55 advantage with 4:41 left in the quarter.
"Shawn was Dirk tonight," said Phoenix's Jared Dudley of Marion, a former Suns star.
Phoenix ended the third quarter with six unanswered points, narrowing the deficit to 74-65.
Sebastian Telfair of the Suns was called for a flagrant foul with 7:07 left, earning an automatic ejection when he hit Dallas' Rodrigue Beaubois in the face and hauled him to the floor on Beaubois' layup attempt.
Beaubois made both foul shots, and when Dallas got the ball back, Lamar Odom's basket extended the Mavericks' edge to 88-74.
The Suns made one last push when Steve Nash's jumper with 2:16 left narrowed the gap to 91-84.
But Marion's hoop with 35 seconds remaining extended Dallas' lead to 93-84, closing out the Suns.
"I wasn't surprised," Gortat said of Marion's production. "He always has good games against us. We've just got to be smarter against him."
Marion's previous season high was 22 points at Utah last Thursday. ... Dallas set a season high with a 32-point first quarter. ... Former Dallas Cowboys running back Emmitt Smith sat courtside with his wife, Pat.