Lillard scored 31 points and McCollum added 28 for the Trail Blazers, who won their seventh straight home game.
Al-Farouq Aminu had 15 points on 6-for-9 shooting -- including 3-for-4 from 3-point range -- and had seven rebounds for the Blazers. Portland also got 12 points from Pat Connaughton and 11 points and 10 rebounds from Ed Davis off the bench.
Andrew Wiggins scored 24 points and Jamal Crawford added 19 off the bench for Minnesota, which had won six of its previous eight games.
Portland broke open a tight game with a 43-point third quarter.
The Blazers won the game at the 3-point arc, making 17 of 31 attempts compared to Minnesota's 6 of 16 from long distance. Portland shot 54.9 percent from the field overall, and the Timberwolves fired at a 53.6 percent clip.
Lillard scored 18 first-half points as Portland climbed back from an eight-point deficit to gain a 54-54 tie at intermission.
Wiggins had 15 first-half points and Crawford 12 for Minnesota, which shot 53.3 percent before halftime.
The Blazers outscored the Wolves 43-30 in the third quarter to take a 97-84 lead into the final period. Lillard led the way with 13 points in the quarter.
McCollum's 3-point shot upped Portland's advantage to 121-102 with 3:38 remaining. Minnesota outscored the Blazers 12-2 the rest of the way, but it didn't matter.
Minnesota sank 12 of its first 16 shots from the field to take a 25-17 lead eight minutes into the game. The Timberwolves took a 29-25 lead into the second quarter.
A Crawford four-point play pushed the Wolves' lead to 47-40 late in the second quarter.
Portland travels to face the Mavericks in Dallas on Friday. Minnesota concludes a three-game West Coast trip with a game against the Golden State Warriors on Thursday.
--Field Level Media
Minnesota | Portland | |
Andrew Wiggins 24 | Scoring | Damian Lillard 31 |
Jamal Crawford 5 | Assists | Damian Lillard 6 |
Karl-Anthony Towns 9 | Rebounds | Ed Davis 10 |
Jeff Teague 7 | Free Throws Made | Damian Lillard 7 |
Nemanja Bjelica 2 | Steals | Al-Farouq Aminu 2 |
Gorgui Dieng 1 | Blocks | Pat Connaughton 1 |
Team | Points | FG% | 3PM-3PA | FTM-FTA | Assists | Rebounds | Blocks | Steals | Turnovers |
Minnesota | 114 | 53.6 | 6-16 | 18-22 | 20 | 33 | 2 | 7 | 9 |
Portland | 123 | 54.9 | 17-31 | 16-21 | 24 | 37 | 1 | 4 | 11 |