The Celtics last beat Dallas in overtime on November 20. It was the last link of his streak of 16 games won, and had problems that night to keep the chain alive.
But in a sense the extra overtime period was played Wednesday night, with the Celtics pushed in the minutes before beating Dallas for the second time this season, 97-90. The Celtics have won their last four games, and six of their last seven.
This meant overcoming a performance of 41.4 shots. Kyrie Irving again finished strong with 23 points with 10 of 18 shots.
The Celtics took the lead four times in the third quarter, only Dallas withdrew it each time and extended the lead to 73-70 by the start of the fourth.
The Celtics, with an ERA of 38.8 percent, had a hard time finding shots against the Mavs area, probably the most effective in the NBA.
But the Celtics returned to lead immediately, scoring the first 10 points of the quarter in a frantic stretch that included a Theis alley-oop and, later in the race, an offensive board and kicked Shane Larkin for a triple.
Larkin then reviewed Dwight Powell for a defensive backboard and fouls, and the hustle was rewarded by the other end for a triple from Terry Rozier for an 80-73 Celtics lead.
And disappeared in an instant with an 8-1 Dallas race.  Irving and Marcus Smart registered with 7:23 minutes to play, and the Celtics responded to this new energy release with a Theis tip-dunk followed by Irving's one-handed float for an 85-81 advantage Celtics with 6:19 to play.