PORTLAND, Ore. -- The Toronto Raptors worked hard in the preseason to improve their offense, but defense remains their calling card.

The Raptors clamped down hard Monday night at Moda Center, holding the Portland Trail Blazers to six points in the second quarter en route to a 99-85 victory.

"We've tweaked our offense, but the major emphasis is still defense," Toronto coach Dwane Casey said. "You're not going to stop great players like (Damian) Lillard and (CJ) McCollum, but our whole emphasis was to make them work for every inch on the court."

Lillard got loose for 25 of his season-high 36 points in the second half, but McCollum struggled to a 5-of-16 shooting night and wound up with 16 points.

DeMar DeRozan scored 21 of his 25 points in the first half, Kyle Lowry contributed 19 points, 10 rebounds and six assists, and Lucas Nogueira chipped in with a season-high 17 points and seven rebounds for the Raptors (4-2).

Portland entered the game as the No. 1 rebounding team in the NBA. Toronto was without starting center Jonas Valanciunas and starting power forward Serge Ibaka, both out with knee injuries.

So how did the Raptors gain a 47-38 advantage on the boards?

"Fear is a mysterious thing," Casey said. "We talked about how they physically just ate us up in an exhibition (a 106-101 Portland win on Oct. 6). They pushed us around, knocked us down. It's one of two things -- either you fight, or you run. Our guys dug in and did a much better job of rebounding the ball."

Portland got off to a hot start, sinking 8 of its first 11 shots en route to a 19-15 lead. DeRozan was sizzling, too, making his first five shots while scoring 13 of the Raptors' first 15 points.

Toronto came back to tie the score at 29 after one quarter.

Portland went more than six minutes without a point and Toronto outscored the Trail Blazers 25-4 to start the second quarter to go in front 54-33. Portland missed 18 of its first 19 shots and finished 2 for 20 in the quarter. The Raptors took a 54-35 edge into intermission.

"We really hurt ourselves in that second quarter," Lillard said. "To score six in a quarter, you're not giving yourself much of a chance.

"(The Raptors) built the lead in that second quarter. We pretty much played them even in the second half, but we weren't able to dig out of the hole."

Casey used his second unit -- including CJ Miles, Jakob Poeltl, OG Anunoby and Delon Wright -- through much of the second quarter.

"It was such an ugly slugfest in that quarter, and they did a great job," Lowry said. "They were switching, talking and rebounding, too."

The Raptors increased the margin to 72-46 midway through the third quarter. Toronto carried an 81-61 advantage into the fourth quarter.

Lillard led the Blazers back, scoring 22 of their first 27 second-half points as they drew within 88-75 with seven minutes to go. Portland got no closer than 12 points the rest of the way.

"Our first quarter was really nice, and the second quarter was really bad," Portland coach Terry Stotts said. "Give credit to Toronto. (The Raptors) were aggressive (defending) our pick-and-rolls, they got their hands on a lot of balls, and when we did get it into the paint, they went after it hard."

Portland, which entered the game 23rd in the league in field-goal percentage (.434), shot only .388.

"Our offense hasn't been at the level we'd like it to be," Lillard said. "When all this comes back around, it's going to be a great day for us.

"We can't put our heads down and lose faith in who are and what we're capable of. We just didn't play well enough on the offensive end to give ourselves a chance tonight."

NOTES: Portland's six points were the fewest in a second quarter in franchise history. The low for any quarter is five points. ... Toronto C Jonas Valenciunas (knee) missed his fourth straight game, but he has practiced the last couple of days and coach Dwane Casey said he is nearing a return. ... Toronto F Serge Ibaka (knee) also sat out the game. ... Portland G Damian Lillard had the 76th 30-point game of his career, second most in franchise history behind Clyde Drexler (130). ... Portland entered the game ranked among the league leaders in several categories, including 3-point percentage (first), free-throw percentage (first), rebound percentage (second), opponents' field-goal percentage (second), scoring (fifth) and opponents' field-goal percentage (fifth).