No other NBA player has played that many seasons with the same team.
"It is good to be back," he said after the game. "Obviously I got a lot of work to do timing-wise, conditioning-wise. I have been running on a treadmill, which is not the same as playing NBA speed against a bunch of 20-year-old athletes."
Nowitzki, 40, had been tied at 20 seasons with Kobe Bryant, who retired from the Los Angeles Lakers after the 2015-16 season.
Nowitzki had surgery to remove bone spurs from his left ankle in April, and the timing was to make sure he would be ready at the start of this season. But the 7-foot German had a setback before training camp, with tendon soreness forcing him to continue rehabbing the injury and missing the first 26 games of the season.
He made his first appearance in the lineup this season with 3 minutes, 27 seconds left in the opening quarter. A minute later, he banked in his first shot in his stint on the court. It was his only basket in his six minutes of play.
"All things considered he did fine, did well," Dallas coach Rick Carlisle said. "This is a challenging situation for Dirk. Coming back in and reaccumulate mid-stream, with no real live practice time to speak of, but he has been busting his butt big time. I respect the hell out of him for what he has done to get back on the floor."
The 2007 MVP said the slow pace of the rehab was to ensure he wouldn't be sidelined again once he returned. The 13-time All-Star has been steadily ramping up his activity for several weeks.
Nowitzki, who led the Mavericks to their only championship as the NBA Finals MVP in 2011, took pride in playing 77 games last season as a 39-year-old. He hoped for a similar number in what could be his final season. Instead, it has been more like 2012-13, when he missed 27 games after preseason arthroscopic surgery on his right knee.
The highest-scoring foreign-born player, Nowitzki is seventh on the career list with 31,187 points. He was sixth to start the season before LeBron James passed him early. James is up to fifth, and Nowitzki needs 233 points to pass Wilt Chamberlain for sixth.
Thursday was the first time Nowitzki had come off the bench since his rookie season in 1998-99.