Michael Beasley scored 27 points and Quentin Richardson had 20, both season highs, as the Heat led from the opening basket. Miami shot 53.3 percent from the field (40 of 75) to offset a career-high 20-rebound effort from Portland's Greg Oden.
The Heat ended a two-game losing streak with a win that may be the type of performance that could give Miami a boost on a four-game Western Conference trip, with games left against Denver, the Los Angeles Lakers and Sacramento.
"This was a great way to start our trip," said Miami's Dwyane Wade, who had 22 points and a season-high 12 assists. "It was a very good team effort against a very, very good team."
Miami attacked Portland from the outset, knowing the Blazers were shorthanded with forward LaMarcus Aldridge sitting out because of a right knee bone contusion. Wade said the Heat were wary of what Brandon Roy might try to do without Aldridge, the team's second-leading scorer with a 14.9 average.
Roy tried to take over, scoring 14 points in the first quarter on the way to leading Portland with 25 points. But it was a difficult game for the All-Star guard who finished 9 of 25 from the field.
"We knew Brandon Roy was going to be aggressive early on, so we wanted to start the game aggressive ourselves," Wade said.
Miami scored the game's first seven points and never looked back. Portland spent much of the game trailing by double digits.
The Heat were coming off home losses to Washington and Boston, so they saw this trip as a chance to make amends.
"I think everybody in that locker room, all 15 guys and the coaches, were looking forward to coming out [West]," Miami coach Erik Spoelstra said.
Beasley was a force throughout his 36 minutes. The second-year forward was 8 of 15 from the field and 11 of 12 from the free throw line. Beasley's 27 points were one short of his career high.
Richardson hit four 3-pointers and grabbed nine rebounds. But Wade's overall performance, particularly the 12 assists, seemed to impress Spoelstra the most.
"We knew they were going to take the ball out of Wade's hands. He had to trust his teammates, and that's what he did," Spoelstra said.
Miami's defense was sensational at times as the Heat built an 88-72 lead after three quarters and led by as many as 17 points. Portland shot 39.1 percent from the field (34 of 87).
"None of this would have been possible if we didn't have the defensive effort and we got the stops we needed," Spoelstra said.
Portland, which lost its third consecutive game, is having significant issues on defense. The Blazers, second in the NBA in points allowed at 90.5 per game, have given up 106, 108 and 107 points in their past three games.
"We just don't have enough guys playing well at the same time," Portland coach Nate McMillan said.
The loss overshadowed Oden's career night of 20 rebounds in just 30 minutes. His previous high was 15 rebounds. Oden had 11 offensive rebounds, which tied a franchise record.
Oden had 13 points and was one of five Blazers to score in double figures. Andre Miller added 18 points for Portland.
Portland rookie F Dante Cunningham made his first start of the season, replacing Aldridge, whose status is day to day. The 6-foot-8 Cunningham, the 33rd pick of the 2009 NBA draft, had six points and five rebounds in 18 minutes. ... Portland has been outscored 93-60 in the first quarter of its past three games. ... Miami ended a four-game losing streak to the Blazers. ... Portland plays eight of its next 11 games on the road. ... The Blazers outrebounded Miami 49-34.