BOSTON – Boston Coach Doc Rivers didn’t hide the fact that his team should beat the injury-riddled New Jersey Nets. Paul Pierce listened and nearly took care of it himself.

Pierce scored nine of his 24 points in a game-breaking third-quarter run and Avery Bradley hit his first career 3-pointer, helping the Celtics to an 89-70 win Wednesday night.

After a listless first half, Boston took over with an 18-3 third-quarter closing run.

“He mainly talked about us,” Pierce said Rivers told the team after the sluggish first half. “He just told us we should win this game with all the injuries they have. We just needed to clean up some things and stop turning the ball over.”

Reserve Brandon Bass scored 15 and grabbed 13 rebounds, and Rajon Rondo had eight points and 12 assists for the Celtics (4-3). Boston has won four straight since dropping all three of a season-opening trip.

Kevin Garnett had 14 points and 12 boards, and Bradley finished with 11 points.

“We just played better, played harder, executed better,” Rivers said of the change after halftime. “I really thought in the first half our defense was terrific; our offense was horrendous.”

Rivers also said Pierce’s play is improving after he missed the first three games with a bruised right heel.

“You can see it,” he said. “He’s getting his rhythm.”

MarShon Brooks, making his first career start, led the Nets with 17 points, and Jordan Farmar had 11. New Jersey has lost six straight since an opening win at Washington.

Nets guard Deron Williams missed the game with a sore right ankle, forward Kris Humphries with a sore left shoulder and center Brook Lopez with a broken right foot. Further depleting their roster, starting forward Damion James had his right foot stepped on late in the second quarter and didn’t play in the second half.

Brooks had 15 in the first half but was hobbled after tweaking his left ankle late in the second quarter.

“He had an awfully good first half for us. He showed how explosive he is offensively,” Nets Coach Avery Johnson said.

The Nets are hoping Brooks and James aren’t out now, too. Brooks had X-rays in the arena after the game, but results weren’t immediately available to the media.

“Damion is more of a foot situation and MarShon is more of an ankle,” Johnson said. “We’ll have more of an update on them (today).”

Boston guard Ray Allen missed the game due to illness.

Neither team shot over 40 percent in the first half that ended with the Nets up 35-34. To add to its weak shooting half, Boston had 10 turnovers.

But in the third quarter, the Celtics just had too much offense — mainly Pierce.

“We just started to execute and run a little bit,” Pierce said. “We kept it simple.”

Bass started the spree with a jumper and Rondo hit a free throw before Pierce nailed consecutive 3s just 34 seconds apart, making it 55-44.

He then hit one free throw before Bradley, who played sparingly in just his second season, nailed his first 3 of his brief NBA career and Pierce hit two more free throws, making it 61-46.