Amir Johnson had 19 points and 12 rebounds, Sonny Weems scored 16 and Jose Calderon tied his career-high with 19 assists as the Raptors won for the first time since a home victory over Sacramento on Jan. 2.
Trey Johnson scored 10 points for Toronto, which has won seven straight home games against Minnesota and nine of the past 10. The Timberwolves, 2-23 away from home this season, lost their sixth straight on the road.
Toronto had not dropped more than 13 in a row since a franchise-worst 17-game skid between Nov. 6 and Dec. 9, 1997. The Raptors have had two other 13-game losing streaks, one in 1998 and another in 2002.
Selected to All-Star game earlier in the day, Minnesota's Kevin Love had 20 points and 15 rebounds for his 35th straight double-double.
The NBA's leading rebounder was added to the Western Conference roster by Commissioner David Stern as a replacement for Houston center Yao Ming, out for the season with an injured left ankle.
Sebastian Telfair had 16 points and Corey Brewer and Darko Milicic each had 15 for the Timberwolves, who have lost eight of nine and 13 of 15.
Timberwolves forward Michael Beasley left late in the second quarter with an injured left ankle and did not return.
Toronto made the first two baskets of the fourth to lead 90-80 with 10:11 left but Minnesota battled back with a 10-2 run over the next four minutes, including 3-pointers from Brewer and Telfair, to make it 92-90 with 6:09 remaining.
After a timeout, Bargnani made one of two from the line, followed that with a 3 and Weems added a jumper as Toronto pushed the lead to eight 98-90 with 4:53 to go.
DeRozan scored 10 points and Bargnani had nine in the first as the Raptors opened an eight-point lead, 27-19, with 3:50 to go in the opening quarter. But Telfair's 3-pointer with less than a second left cut Toronto's lead to two, 33-31, after 12 minutes.
Beasley called timeout and went to the locker room with 2:38 remaining in the second, unable to put weight on his left foot. Toronto led 59-55 at the half.
Bargnani scored 11 points in the third as the Raptors took an 86-80 lead into the final quarter.
Notes: The Timberwolves shot 12 for 30 from 3-point range. ... Minnesota G Luke Ridnour missed his second straight game because of personal reasons, while G Wayne Ellington was also absent for personal reasons. ... Toronto was without G Jerryd Bayless (sprained right knee) and G Leandro Barbosa (right hamstring). Barbosa, who has missed the past 11 games, returned to practice Thursday. ... Calderon also had 19 assists against Chicago on March 29, 2009.