
Roy scored 16 of his 24 points in the decisive final quarter, and the Trail Blazers handed the hapless Heat its season-high 12th consecutive loss, 98-91 on Friday night.
"Brandon just did a nice job of finishing plays, creating defence for us," Portland coach Nate McMillan said. "He knew this was a big game and he responded like an All-Star who says 'I'm going to carry this team. I'm not going to let this team lose.' You could see it in his face."
Travis Outlaw had 18 points, LaMarcus Aldrdidge added 14 for the Northwest Division-leading Blazers (24-15) who improved to 19-3 since December 2.
Dwyane Wade poured in 37 points, but the flashy All-Star guard had just two in the final frame when the Eastern Conference-worst Heat (8-30) was outscored 29-15, matching the third-longest slide in franchise history.
"Everybody is down," said Heat centre Shaquille O'Neal, who had 20 points and 11 rebounds. "Everybody is humiliated and embarrassed. But I've seen people in worse situations. We've got to keep fighting, and learn how to win again."
Trailing by 11 in the third quarter, Wade erupted for a franchise- record 20 points, including 17 in a row, and the Heat closed on a 14- 0 run to take a 76-69 advantage.
"The third quarter was probably the best quarter we've played in two years around here," said Wade. "We thought that was the turning point, but it wasn't."
But Wade went cold, missing six-of-seven shots in the final period. Roy, meanwhile, torched the Heat for 14 points during a pivotal 19-2 surge, opening up an 88-78 advantage with 5:02 remaining.
Roy's two free throws made it 90-82, but three-pointers by Ricky Davis and Jason Williams drew the Heat to within 90-88. Davis made a steal, but Udonis Haslem and Wade missed jumpers that would have knotted the score.
At the other end, Roy found Outlaw for a jumper, and James Jones buried a three-pointer, pushing the cushion to 95-88.
Daequan Cook answered with a quick triple of his own, pulling Miami to within 95-91 with 28 ticks left. After Outlaw made one-of-two free throws, he intercepted Williams' pass and sank both free throws to seal the win.
"We did a great job of responding in the fourth quarter when things got tough," Roy said. "We showed a lot tonight."
Elsewhere: Boston Celtics 116, Philadelphia 76ers 89 Paul Pierce scored 14 of his 22 points in the third quarter, Ray Allen had 10 of his 23 in the final frame, and the league-best Celtics (32-6) ran away from the Sixers.
Andre Iguodala netted 17 points for visiting Philadelphia (15-25) which was outscored 62-32 in the second half.
Sacramento Kings 100, Detroit Pistons 93 Kevin Martin scored 24 points and Ron Artest had 18, including a key three-pointer down the stretch, giving the visiting Kings a sweep of the two-game season series against the Pistons.
Chauncey Billups led the Pistons (29-11) with 28 points and Richard Hamilton added 24.
Phoenix Suns 115, Minnesota Timberwolves 95 Amare Stoudemire scored 23 points, and Steve Nash had 17 with 13 assists as the Western Conference-best Suns sent the Timberwolves to their 15th straight road loss.
Al Jefferson had 27 points and 14 rebounds for the league-worst Timberwolves (5-33), who dropped to 1-19 on the road.
New Orleans Hornets 112, Charlotte Bobcats 84 David West scored 28 points, Peja Stojakovic had 17 with five three-pointers, and the Hornets moved atop the Southwest Division standings.
Emeka Okafor led the Bobcats (15-24) with 13 points.
Memphis Grizzlies 124, Seattle SuperSonics 100 Mike Miller scored 25 points, Spain's Pau Gasol had 24 points with 12 rebounds and the Grizzlies snapped a five-game slide by sending the SuperSonics to their ninth straight loss.
Rookie sensation Kevin Durant netted 22 points for visiting Seattle (9-30) which hadn't lost nine in a row since the 1972-73 season.
Golden State Warriors 119, Chicago Bulls 111 Baron Davis tied his career high with 40 points, including six 3-pointers, and Stephen Jackson had half his 24 points in the final quarter, carrying the visiting Warriors past the Bulls.
Ben Gordon led the Bulls (15-23) with 29 points and Argentine Andres Nocioni added 28.
Utah Jazz 106, LA Clippers 88 Carlos Boozer had 19 points with 10 rebounds, and the Jazz beat the Clippers in Utah for the 30th time in the last 31 games.
Corey Maggette led the Clippers (11-24) with 20 points while Chris Kaman had 16 points and 16 rebounds.
Toronto Raptors 89, Atlanta Hawks 78 Chris Bosh had 13 of his 35 points in the fourth quarter, helping the Raptors to their fifth victory in the last six games.
Joe Johnson led the visiting Hawks (17-19) with 25 points.
Washington Wizards 111, New York Knicks 98 Antawn Jamison scored 32 points, Caron Butler had 22 and the host Wizards stopped the Knicks' season-high three-game winning streak.
Quentin Richardson topped the Knicks (12-27) with a season-best 21 points.
By Paul Levine, dpa