The Portland Trail Blazers held the upper hand most of the way only to be overtaken in the fourth quarter of a 117-111 loss in Dallas on Thursday.
Shaedon Sharpe hit a step-back 3, then swiped a steal and fed Toumani Camara for another long ball to put the Blazers up 10 as the clock ticked under five minutes to play.
But the next 16 points went to the Mavericks, including the go-ahead 3-pointer by P.J. Washington with two minutes left. Quentin Grimes followed with a three-point play while being knocked to the floor along the baseline to secure the victory with 30 seconds left.
Jaden Hardy came off the bench for Dallas and scored a game-high 25 points, while Washington added 23. Anfernee Simons and Shaedon Sharpe shared the lead for the Blazers with 22 points apiece.
Portland (13-24) went 2-3 on its five-game road trip and returns home to face Miami at 7 p.m. Saturday at Moda Center.
The Blazers opened up to a 28-18 lead after 3s by Henderson and Dalano Banton on back-to-back possessions.