Beaubois had seven points and two assists in a 17-4 run that gave Dallas the lead for good to start the fourth.
Reserves Darren Collison and Brandan Wright each scored 13 to pace a Mavericks bench that outscored the Cavaliers’ 60-19.
Cleveland’s Dion Waiters had 21 points and Shaun Livingston chipped with 13. The Cavaliers, who were playing their second game without All-Star Kyrie Irving, shot 37 percent and turned the ball over six times in the fourth quarter.
The Mavericks, who are three games behind the Los Angeles Lakers for the final playoff spot in the Western Conference, opened a stretch where they play eight of nine at home. Dallas was coming off a 92-91 loss at San Antonio on Thursday night and struggled early. Led by the seldom-used Beaubois, the bench helped the Mavericks pull away in the fourth.
Beaubois scored to put the Mavericks up 71-70 early in the fourth. The French guard found Wright for a layup and then drained a 3-pointer to extend Dallas’ advantage to 80-72.
Collison and Wright had baskets to finish off the 17-4 run, putting the Mavericks up 84-72 with 6:17 left.
The 6-foot-2 Beaubois, who had scored only nine points in Dallas’ last five games, punctuated his game later in the fourth with an emphatic dunk on a baseline drive.
The Cavaliers dropped to 5-11 without Irving in the lineup. The reigning Rookie of the Year is expected to miss three to four weeks — and possibly the rest of the season — with a left shoulder strain. Dallas guard Chris Wright, who is diagnosed with multiple sclerosis and returned to basketball last July, came into the game with 41 seconds left and scored the Mavericks’ final basket.
The Mavericks didn’t lead until the third quarter.
O.J. Mayo found Collison for a layup and Jae Crowder connected on a 17-footer to finish off the surge and give Dallas a 57-54 lead with 5:06 left in the third.
Collison banked in a 20-footer with 1.3 seconds left in the third. Livingston caught a long pass and hit a turnaround jumper at the buzzer to give the Cavaliers a 68-67 lead.
Crowder had a season-high 14 rebounds and Dirk Nowitzki scored 13 points on 6-of-17 shooting for the Mavericks.
The Cavaliers jumped out to a 13-4 lead six minutes into the game. Dallas missed nine straight shots at one point as Cleveland built its early advantage.
After Cleveland stretched its lead to 11 early in the second quarter, Dallas went on a 16-6 run to get within a point. Beaubois scored six straight for the Mavericks, including a 3-pointer that trimmed the Cavaliers’ lead to 33-32.
NOTES: Dallas F Shawn Marion, who missed his fifth straight game Friday night, was diagnosed with a strained left calf after he had an MRI on Friday. Mavericks coach Rick Carlisle said the injury was improving, but he did not give a timetable for Marion’s return. . Cavaliers G Wayne Ellington didn’t play because of a sprained left ankle. . Cleveland’s C.J. Miles is a Dallas native and attended Skyline High School, which is a few miles east of the American Airlines Center. The guard scored eight points and grabbed five rebounds.