James Harden shook off foul trouble to score 20 points for the Rockets, who earned their eighth straight win. Clint Capela added 17 points and 12 rebounds.
Gordon snapped a tie with a layup with 3:42 left, and P.J. Tucker’s 3-pointer put Houston up by five with 1:29 remaining.
Dwight Powell’s dunk cut the lead to one with 31 seconds left. After Harden missed a runner, the Mavericks had a final chance to win.
But Paul made a clean block on Brunson’s running jumper at the buzzer.
Dallas lost for the 10th time in 11 games.
Luka Doncic had 19 points and a career-high 15 rebounds for the Mavericks, and fellow rookie Brunson finished with 18 points.
Doncic appeared to hurt his left knee in the fourth quarter and limped off the court for a timeout with 4:17 to play, but he stayed in the game.
Harden picked up his fifth personal 20 seconds into the second half when Doncic took a charge. He re-entered with 3:03 left in the third and converted a three-point play and then a 3-pointer to put the Rockets up 79-70.
Dallas closed to 86-84 when Brunson fed Dorian Finney-Smith for a fast-break dunk, capping a 12-2 run with 7:21 to play. Tim Hardaway Jr. hit a 3 with 4:04 left to tie it at 89.
Harden had scored 30 or more points in 47 of his 61 games this season, including 37 of the last 38 entering Sunday.
Gordon scored 10 points during a 15-7 run to start the second quarter, helping the Rockets to a 58-54 halftime lead. Brunson drew a charge for Harden’s fourth personal foul with 15.3 seconds left in the half.
Dallas star Dirk Nowitzki scored six points. He needs 35 more to pass Wilt Chamberlain for sixth place on the NBA’s career scoring list.
Rockets: Coach Mike D’Antoni said Kenneth Faried would return to the lineup Monday after missing five games with a left hip contusion, and Nene would rest on the second half of the back-to-back.
Mavericks: Coach Rick Carlisle said he didn’t feel urgency to manage the 20-year-old Doncic’s minutes deep into his rookie season: “A big part of this last segment of the season is him getting a real taste for what it means to have to carry a load.” Doncic played 74 games for Real Madrid last year in league and tournament play; he has played in 62 of Dallas’ 66 games this year.
Rockets: Start a four-game homestand Monday against Charlotte.
Mavericks: Host San Antonio on Tuesday.