TORONTO -- Despite concluding a stretch of four games in five nights, with travel, the Toronto Raptors were able to pour it on in the fourth quarter to outscore the Celtics 26-17 and defeat Boston 105-91 Friday.

Kyle Lowry led the way with a game-high 32 points, five assists and four rebounds.

R.J. Hunter hit a shot from beyond the arc with less than a minute remaining in the third quarter to cut Toronto's lead to five, 79-74, through three quarters.

However, Lowry turned it on in the fourth, scoring 15 points on 3-of-5 shooting from beyond the arc. The 29-year-old said he had a little extra motivation by way of a Celtics fan behind the Boston bench, who was chirping him all night.

"It was to a fan back there," Lowry said of his gesture during the final period. "I would never disrespect a bench. Those guys, that coaching staff -- I have the ultimate respect for those guys down there. It was definitely not towards them and I went and told them it was for a fan who was talking trash the whole game.

"Just talking trash the whole game, but I think I got the last word in that one."

Toronto (47-21) has now won three straight and 12 of 15.

Luis Scola finished with 17 points and three rebounds. DeMar DeRozan added 15 points, seven rebounds and six assists.

"It's definitely big because you're playing against teams that are fighting for something," said DeRozan of the four-games-in-five-days stretch. "It's the end of the season, you have every excuse in the world. Just to go out and play aggressive like we did, on the defensive end after these four games in five nights, it's definitely great."

The Celtics were led by a team-high 20 points from Isaiah Thomas. Evan Turner chipped in with 12.

The loss was the fourth consecutive defeat for Boston (39-30), matching a season-high.

"Never really in it," said Celtics coach Brad Stevens. "I guess we got back in it in the third quarter and then we had a cluster of errors there that led to transition points and kind of got us back out of it."

Toronto used a 6-0 run to push its lead to 11 early in the fourth quarter.

Then, with just over seven minutes remaining, Lowry hit back-to-back 3-pointers to give Toronto a 17 point lead.

Lowry registered his 21st career game of 30-plus points in the win.

"He was big," said Raptors coach Dwane Casey. "He came through and again he played with force. That is what you have to do. If you don't play with force in this league people will take your reputation and everything you have."

Raptors forward Patrick Patterson left the game with 7:07 remaining in the fourth quarter due to a left foot contusion and did not return. X-rays on his left ankle were negative.

The Celtics outscored the Raptors 17-5 on the break to cut the Raptors' lead to six with two minutes remaining in the third. Thomas led the comeback with 12 points.

Lowry had nine second-quarter points on 2-of-3 shooting as the Raptors led 55-41 at intermission.

The Celtics were led by eight first-half points from Thomas while Jared Sullinger had six points.

Lowry drained one of his two three pointers of the half with three minutes remaining in the second period, giving the Raptors their largest lead, 52-34.

Boston only trailed by 16-plus points four times in 51 games before Wednesday. Friday was the second time it happened in as many games.

"I don't think anyone is discouraged," said Amir Johnson. "There are some spurts where we did play Celtics basketball. We have to put it together for the full 48 minutes."

Scola started hot, leading the Raptors with 17 first-quarter points as Toronto held a 30-14 lead after one period. His 17 points were a career high for points in the first quarter of a game.

"That's what the old man does," said DeRozan. "The engine runs well in the beginning. He's like an old-school Cutlass, he gets you to where you need to go, but don't rely on him for any road trips."

NOTES: C Jonas Valanciunas (left hand contusion) was active after missing two games. Bismack Biyombo started in Valanciunas' place. ... F James Johnson missed his second game due to plantar fasciitis in his left foot. G Norman Powell made his third consecutive start as a result. ... G Evan Turner started for the Celtics in place of G Marcus Smart. ... F Jae Crowder missed his third game due to a right ankle sprain. ... F Jonas Jerebko missed his second game due to a sore left ankle.