04/13/2012 09:50 EDT | Updated 06/13/2012 05:12 EDT

DeMar DeRozan scores 22 as short-handed Raptors hold off Celtics 64-79

TORONTO - The Toronto Raptors want DeMar DeRozan to assume the role of fourth-quarter finisher.

He played the part Friday night, shutting the door on one of the hottest teams in the NBA.

DeRozan scored 13 of his game-high 22 points in the third quarter and added four crucial free throws in the final 30 seconds as the short-handed Raptors overcame a spirited Boston comeback on the way to an 84-79 win over the Celtics.

With Toronto's 15-point edge whittled down to one, DeRozan drove baseline and collided hard with Celtics forward Paul Pierce, drawing the foul and nearly making the shot. He buried both free throws to put Toronto up three, then hit two more on the next possession as the Raptors (21-39) ended a four-game losing skid.

"I just try to be aggressive," DeRozan said. "A couple plays I saw an opportunity to get to the basket and I did. I should have made it and had an and-one ... but that's what it's all about. Getting to the line and knocking down your free throws."

DeRozan has been challenged by Raptors head coach Dwane Casey to take the ball to the rim more often, using his explosiveness off the dribble to generate some much-needed offence for a team sitting near the bottom of the NBA in points per game. While he struggled from the field against Boston – shooting just 4-for-14 – he made all 13 of his foul shots, highlighted by the four that effectively put the game away.

"My shots weren't falling so I tried to get some easy points, especially from the free-throw line," he said.

Injuries to forward-centre Andrea Bargnani (strained left calf, out for season) and point guard Jose Calderon (swollen right eye, day-to-day) left the Raptors with NBA Development League callups Alan Anderson and Ben Uzoh in the starting lineup against a team that had gone 19-7 since the all-star break. Casey praised the efforts of both players afterward.

"They did an excellent job of coming in offensively and defensively and taking it to a team that has been one of the hottest since the all-star break," Casey said. "I didn't sleep at all last night just worrying about getting the ball across half court."

The Celtics (34-25) may have trouble sleeping themselves, having dropped a winnable game in the opener of a dizzying stretch that will see them play six games in different cities over an eight-night span. The Toronto stop was the first of back-to-back-to-back games for Boston, which held Toronto to just 23.1-per cent shooting in the opening half but went through its own frigid spell – scoring just 11 points on 4-for-17 shooting in the third quarter – and couldn't recover.

"I just thought the way we set the tone to begin the third quarter just changed the game," said Celtics head coach Doc Rivers. "I told our guys you can never activate a team and I thought we did that. They haven't won a lot of games and once they felt like they had a chance to win, they made great shots and made great plays.

"I thought we put ourself in that position."

Pierce said he was surprised his team didn't come out fresher at the beginning of a tough stretch of basketball.

"I don't know if it's fatigue from going through a rough schedule, end of the week ... you know it's crazy because we have three games in a row," he said. "We should have come out with better urgency in the third quarter.

"Right now we have a lot to play for, we are playing for playoff positioning and that has to be the mindset regardless of who steps on the court. So with the possibility of moving up to the three or four seed these are must-win games for us."

Boston remained three points clear of Philadelphia atop the Atlantic Division following the 76ers' 95-89 loss to the New Jersey Nets.

Celtics point guard Rajon Rondo made history in the loss, dishing out 12 assists for his 20th straight double-digit effort. It's the longest such streak since Utah's John Stockton put together a 29-game run from Jan. 25-March 30, 1992.

Notes: The Celtics were without SG Ray Allen, who is hobbled by a sore right ankle and did not travel to Toronto. He is considered day-to-day. ... Raptors F Linas Kleiza returned to the lineup after missing nearly the entire second half of Wednesday's loss to Philadelphia with a sore knee. ... Calderon is expected to travel with the club to Atlanta for the opener of a home-and-home series with the Hawks on Sunday. ... Toronto finished with just nine first-half field goals, narrowly avoiding the franchise low of seven set Jan. 11, 2010 in Indiana. ... Boston plays just twice over the final six days of the regular season, wrapping things up with home dates against Miami and Milwaukee.