BOSTON - The first nine-and-half minutes of the Boston Celtics' NBA season wasn't going to plan.

Playing what many consider the worst team in the league, the Philadelphia 76ers, the Celtics found themselves down 26-17. And 18 of those Sixers points had come in the paint.

The C's were getting worked down low, and it wasn't pretty.

Then their big free agent signing, Amir Johnson, was subbed into the game. That Sixers offense? Halted.

With Johnson in the game, the C's scored the final four points of the 2:31 remaining in the first quarter - and that stingy defense carried over to the second quarter.

From the start of the second quarter to when Johnson was subbed out with 6:17 remaining, the Celtics went on a 14-2 run and led the Sixers by seven points.

It was the most impressive stretch of play in the game, as the second quarter proved to be the real difference. Boston shot 50-percent (11-22) in that quarter compared to the Sixers' 22.7-percent (5-for-22).

Philly only had 10 points in the paint that quarter, too.

"I thought Amir coming in the game was really good at the rim protecting the rim for us and tipping balls and keeping balls alive and altering shots and those types of things," Brad Stevens said. "He reacted well to drives."

Johnson finished with 15 points, but the offense is a bonus to the presence he provides on the other side of the ball. He had four defensive rebounds and two blocks.

"He's a rim protector," Jae Crowder said. "I've played against him a couple years. I know he's a presence down there. He played with [Jonas] Valanciunas [in Toronto]. But he's a good rim protector. He's not afraid to go up vertically and try to go up and block a shot. So he knows how to play defense, he knows how to come over and make a play."

The Celtics didn't have much of a rim-protecting big man last season, and were considered by many to be a small team. But with that extra security blanket on the last line of defense, the guards know somebody's got their back.

"It give us a lot of confidence because he knows his role, he knows where to be on the defensive end and he's a guy that's always talking," Isaiah Thomas said. "So for the guards that gives us a lot of help. Sometimes we can gamble a little bit more than others. But he's a hell of a basketball player and has a high basketball IQ."