The Blazers held LeBron James to 15 points, snapping his 54-game streak with at least 20 points that dated back to last season.
Miami led by as many as 13 points but lost for the fifth time in eight games.
Nicolas Batum led the Blazers with 28 points, and LaMarcus Aldridge had 20 points and 15 rebounds. Matthews finished with 18 points.
Chris Bosh had 29 points for the Eastern Conference-leading Heat.
PACERS 81, KNICKS 76
INDIANAPOLIS (AP) — Paul George scored seven points in a 13-0 fourth-quarter run and finished with 24, leading Indiana past short-handed New York.
The Pacers have won 12 of 15, including a sweep of the other two Eastern Conference division leaders — Miami and the Knicks — this week.
New York was led by J.R. Smith with 25 points on a night they clearly missed Carmelo Anthony, who was suspended for Monday's postgame confrontation with Boston's Kevin Garnett. Without Anthony, the Knicks fell nine points below their previous season-low point total (85).
New York rallied from a 49-38 third-quarter deficit and started the fourth with a 60-58 lead.
MAVERICKS 117, KINGS 112, OT
SACRAMENTO, Calif. (AP) — O.J. Mayo had 24 points and 10 rebounds, Vince Carter scored 23 points off the bench and Dallas rallied from 17 points down to beat Sacramento in overtime.
Shawn Marion added 19 points and 10 rebounds to help the Mavericks snap a four-game losing streak. Dallas, which had lost 10 of 11, finished its short road trip 1-2.
With the franchise's possible sale and relocation to Seattle on the minds of Kings fans, DeMarcus Cousins had 29 points and nine rebounds before getting ejected in overtime for elbowing Carter in the face. Tyreke Evans scored 20 points and Isaiah Thomas had 18 points for the Kings, who lost their third straight game.