10/10/2014 10:02 EDT | Updated 12/10/2014 05:59 EST

Lowry, DeRozan lead Toronto Raptors to 116-109 win over Boston Celtics

TORONTO - Coach Dwane Casey has emphasized defence from Day 1 of camp, stressing his team needs to be at its defensive best by the time the bright lights of the regular season are switched on.

It took until the fourth quarter Friday night, but finally the Toronto Raptors looked like they were listening in a 116-109 pre-season victory over the Boston Celtics.

"Defence" was the difference, said Kyle Lowry, in a fourth quarter that saw Toronto outscore the Celtics 29-16.

"Those guys, they missed some shots (in the fourth) that they made in the first three quarters but we really locked into our defensive schemes and really, really paid attention to what they were doing and made some good adjustments at halftime," he said.

Lowry and DeMar DeRozan scored 18 points apiece to lead the Raptors (2-1), while Patrick Patterson added 17 points in his first action of the pre-season.

Amir Johnson and Greivis Vasquez finished with 13 apiece, while Jonas Valanciunas had 11 points to go with nine rebounds.

Casey hadn't seen a decent defensive effort this pre-season and Friday looked to be more of the same in a game that saw long stretches of swapping bucket for bucket for the first three quarters.

"Sometimes you've got to win any kind of way, and tonight we were able to outshoot them," Casey said. "Again, I will say, we can't live a long way playing that way. You're not going to outshoot everybody, there are going to be nights that ball's not going to fall, but I did like our focus, I thought our energy was there, our rebounding was there, and that's all you can ask."

Avery Bradley topped the Celtics (2-1) with 22 points, while Marcus Thornton had 19.

Kelly Olynyk, who was born in Toronto and moved to Kamloops, B.C., when he was 12, had eight points for the Celtics. His Canadian teammates Joel Anthony of Montreal and rookie Dwight Powell of Toronto didn't play.

The Raptors shot 50 per cent from the field, but allowed Boston to shoot 49 per cent, and they gave up 37 points to their visitors in the third quarter in front of 16,729 fans at Air Canada Centre.

The Raptors trailed 93-87 going into the fourth quarter, but chipped away at the deficit. James Johnson cut the difference to two points — and provided one of the highlights of the night — when he soared in for a put-back on a Patterson miss with just over eight minutes to play.

The Raptors kept their foot on the gas from that point on and when Lowry grabbed his own rebound and dribbled in for a nice floater, it put Toronto up 106-98 with about six minutes left. The Raptors dominated to the final whistle.

Lowry looked in regular-season form down the stretch, and said it's all about "trying to get my rhythm."

"It's pre-season but we're still trying to put our emphasis on games and trying to get our defensive identity and our intensity going and create good habits," he said.

Casey was pleased with the performance of Patterson, who sat the first two games with a sore hand and sore knee.

"Huge," Casey said of his game. "I thought he made one big bucket off the dribble, off the bounce that was huge. He gave us 20 minutes and 17 points, I thought that was big, but just his defensive energy with seven rebounds was huge. He brings a defensive presence and energy to the court that you can't really put a premium on."

Boston coach Brad Stevens also lamented his team's lack of defensive effort.

"We gave up 60 in the first half," Stevens said. "We went on a spurt in the third quarter where we played OK defensively but to their credit they spread us out and made plays. We're going to have to get a lot better."

Toronto's starters — Lowry, DeRozan, Terrence Ross, Johnson, and Valanciunas — played the majority of the first quarter, and took a 31-21 lead into the second, DeRozan leading the way with nine points.

Bradley poured in 17 points in the second as the Raptors' lead nearly vanished. Toronto was up 60-56 at halftime.

Defence was virtually non-existent in the third as the Raptors allowed Boston to shoot 60 per cent from the field and take a nine-point lead with just under a minute left in the quarter.

Ross, who injured his knee and ankle late in Toronto's pre-season opener, returned after missing Toronto's 113-106 loss at Sacramento on Tuesday. Greg Stiemsma, injured in practice Tuesday, didn't pass a baseline concussion exam Friday. He'll undergo another test Saturday.

Lucas Nogueira, who has yet to play this season due to a groin strain, sat out the game.

The Raptors are in New York to face the Knicks on Monday in the first of three straight on the road. They return to Toronto to host Maccabi Haifa on Oct. 22.

The Raptors open the regular season at home to the Atlanta Hawks on Oct. 29.