The Blazers outscored Dallas by a 35-15 margin in the fourth quarter to even their first round series at two games apiece. Portland became the third team in the NBA's shot clock era to win a playoff game when trailing by 18 points or more entering the fourth quarter.
Previously, Boston overcame a 21-point deficit to beat New Jersey 94-90 on May 25, 2002; and Phoenix trailed by 18 before beating Houston 124-117 on May 11, 1994.
At one point in the second half, the Blazers were down 23 points.
Brandon Roy scored 18 of his game-high 24 points during a fourth quarter performance in which he made 8 of 10 field goals and recorded four assists.
Roy tied the game on an improbable four-point play with 1:06 left, making a three-pointer from the top of the key as Shawn Marion hacked him.
"When I shot it, I threw it up (and) then I started to look toward the ground to land," Roy said. "I looked up and it went in. I'm thinking, 'Oh, this is going to be one of those finishes.'"
For Roy, the performance was a complete reversal of Game 2 when his minutes were limited and he very openly expressed discontent with head coach Nate McMillan.
"Just one of those feelings where I was happy to have their support. It still just doesn't feel real yet. It was just an unbelievable game. To come back, with everything I've been through this season, it just all kind of came into that moment right there on the court with guys grabbing me and just cheering me on. It was real special."