The already injury-riddled Blazers suffered another blow when Matthews sprained his right ankle late in the second quarter. Matthews, who scored 17 points in his first 18 minutes, rolled his ankle as he planted his right foot on a drive to the bucket with just over two minutes remaining in the half. He walked to the locker room with assistance.
"That's the ankle that's been messed up," said Matthews, who had a team-high 19 points. "I heard some pops, heard and felt some pops. It calmed down and I was able to return again."
Matthews started the second half but left after 19 seconds when he suffered a knee-to-knee hit. He returned to start the fourth quarter but scored just two points.
"The way he walked off the court in the first half I thought there was no way he was coming back," Denver coach George Karl said.
It's another in a rash of injuries to hit Portland, which has lost 164 man games to injury this season. Five players have had knee surgery this year, including Greg Oden, Marcus Camby, Brandon Roy and rookie Elliot Williams. Williams and Oden are out for the season, while Roy and Camby are expected back after the All-Star break.
In addition, center Joel Przybilla missed the first 18 games of the season with a right knee injury and a stomach flu.
Matthews vowed the ankle, which he said he initially hurt in practice two weeks ago, won't keep him out of the lineup.
"I'm always going to come out here and play for my teammates," he said. "I can't afford to get hurt, can't afford to let something slow me down. If I'm walking, I'm good."
LaMarcus Aldridge added 18 points and nine rebounds for Portland.
Portland stayed in the game despite Matthews' limited play. The Blazers led 68-67 late in the third when Billups hit two 3-pointers to give Denver a 73-70 lead.
Two free throws by Aldridge made it 81-74, but Smith hit a 3-pointer and Arron Afflalo made a short jumper to give Denver a 12-point lead.
"The second half they got going," Portland coach Nate McMillan said. "Chauncey started to knock down some shots, Smith got hot and we gave up 64 points in the second half."
Andre Miller cut it to nine with a free throw and Portland had a chance to slice deeper into the lead, but a turnover led to a Smith dunk and the Nuggets were never seriously threatened.
The Nuggets didn't think Matthews' injury was a factor.
"We were focused in the third quarter," Billups said. "It didn't matter who was out there.
The Trail Blazers, coming off a win Tuesday night against San Antonio, led by one at halftime. Portland shot just 40.5 percent before the break but went 7 for 9 from 3-point range to get the lead. Miller's floater in the lane just before the halftime buzzer gave them the lead.
The Nuggets stayed close by outrebounding the Blazers 23-14 and shooting 50 percent from the field to that point.
Al Harrington returned from a strained left foot, which meant the Nuggets had their full team, including coach, available for the entire game for the first time in more than a year. ... Including last season, the Trail Blazers' last four games in Denver have come on the second night of back-to-back games. ... Denver is 20-2 at home against Portland since the 2000-01 season.