01/20/2016 21:56 EST | Updated 01/20/2017 00:12 EST

DeRozan powers Raptors to sixth straight victory, 115-109 over Celtics

TORONTO — DeMar DeRozan poured in 34 points, Jonas Valanciunas added 19 points and 12 rebounds and the Toronto Raptors extended their winning streak to a season-high six games with a 115-109 victory over the Boston Celtics on Wednesday.

Luis Scola had 18 points for the Raptors (27-15), Terrence Ross chipped in with 14, including four three-pointers, and Kyle Lowry had 14 to help Toronto improve to 19-8 against Eastern Conference opponents this season.

Isaiah Thomas led the Celtics (22-21) with 21 points and 10 assists, Avery Bradley had 19 points and Canadian Kelly Olynyk contributed 18.

Former Raptor Amir Johnson, in his first game back in Toronto since signing a free-agent deal with the Celtics this off-season, had two points as Boston lost for the fifth time in six road games.

The Celtics tied the game 105-105 with 3:20 on a Bradley jump shot with 3:20 left. But Lowry and Ross hit consecutive threes moments later to restore Toronto's lead. 

Toronto scored 40 points in the third quarter, including 16 from DeRozan alone, to head into the fourth up 96-90.

The Raptors capped a 10-2 run early in the third with a three-pointer from Lowry to give them a 70-68 lead, their first of the second half.

The Celtics outscored Toronto 35-21 in the second quarter and took a 62-56 lead into halftime.

A floating jump shot from Evan Turner with 5:19 remaining in the half cut the Raptors' once 13-point lead to one and Amir Johnson's dunk with 2.9 seconds left — his first basket of the game — put Boston up by six.

Toronto went on a 9-0 run midway through the first quarter en route to a 35-27 lead after 12 minutes. Scola led the way with 11 points and DeRozan poured in 10 as the Raptors outshot Boston 20-8 in the paint.

NOTES: Lowry passed Damon Stoudamire for third place on team's all-time assist list with his fourth of the game in the first half. ... The Raptors continue their seven-game home stand against the Miami Heat on Friday. Boston visits the Chicago Bulls Friday night.

Melissa Couto, The Canadian Press