Marcin Gortat crowded Boston Celtics center Jared Sullinger as he drove baseline, sized him up then slapped Sullinger’s shot right into the hands of Bradley Beal.

Beal tossed the ball ahead to John Wall, who raced up the court, sucked in the defense and flipped the ball over to Trevor Ariza for a three-pointer. Ariza’s basket completed a stunning run in which the Washington Wizards turned an eight-point deficit into a five-point lead in roughly four minutes.

After the shot dropped, TD Garden fell silent. Wall glared back at his bench, marveling at the cold-blooded and methodical precision of a 14-1 rally that propelled the Wizards to an impressive 106-99 victory over the Celtics.

Ariza calmly backpedaled and said he told himself, “Okay, we fought back. Now let’s not stop here. Let’s keep going, let’s keep stepping on them and let’s run away with this one.”

The team that once found a way to repeatedly fumble in crunch time, that never had enough energy to finish after climbing back from huge deficits, is suddenly making the critical plays and demoralizing opponents in their own buildings.

The Wizards (12-13) overcame an 18-point deficit to claim their third consecutive road win for the first time since April 2012.

Washington got a game-winning layup by Beal in a one-point win in New York to start the week, a huge offensive putback by Gortat and a backbreaking three-pointer by Beal in Brooklyn and a lift from Ariza and Wall in Boston after a sloppy start.

“We don’t let anything rattle us too much,” Ariza said after making five three-pointers and scoring a game-high 27 points. “We’re starting to learn that.

We’re starting to mature as a team and when you don’t get too high or too low and just play, it’s a long game. Teams go on runs and we were down early, but we still had a lot of game left and stuck with it.”

Ariza said recently that the Wizards’ struggles to close out games would eventually make them better, that their unfamiliarity with those situations would morph into experience. Now Washington is playing with a confidence that it will make the plays that matter in the end.