Maybe this is the win this Celtics team needed. It was hard to see this one coming, especially with five Celtics regulars sidelined by injury against a Magic team that won 11 of its first 15 games, but the C’s put together their best stretch of basketball in a 87-56 welcome home victory against Glen Davis & Co. at the Garden on Monday.

Paul Pierce (19 points, 7 assists) once again led the offensive charge, with a little help from friends Kevin Garnett (14 points, 10 rebounds) and Brandon Bass (19 points, 8 rebounds). Meanwhile, starting in place of the injured Rajon Rondo, guard Avery Bradley (3 steals) wreaked havoc on the defensive end to help the C’s (7-9) hold Orlando to 16-of-65 shooting (24.6%) — the best defensive effort of this Big Three era.

Davis scored just six points (2-9 FG) but grabbed 11 rebounds, and Dwight Howard led the Magic’s anemic offensive effort with 18 points (4-15 FG) and 14 boards.

WHAT WENT RIGHT

Defending their life: Led by defensive-minded starters Garnett and Bradley, the Celtics put together their best defensive game of the season. They held the Magic to just 11-of-38 shooting (28.9%) before the break, and actually improved upon that in the second half (5-27; 18.5%). The C’s recorded six blocks (shockingly, none by rejection artist Greg Stiemsma) and six steals by halftime, building an early lead — something that escaped them through their 6-9 start.

Familiar foes: Lost in the drama surrounding Big Baby’s return to the Garden was the fact Bass was also facing his former team, as the two former LSU teammates were traded for each other after the lockout. One of few healthy bodies coming off the bench, Bass reached double digits by halftime and gave the C’s a much-needed boost against his old teammates.

Avery Bradley, defensive stopper: The Celtics sophomore guard gave veteran Magic point guard Jameer Nelson problems all night long, picking his pocket twice, forcing a jump ball and altering his shot — all in the third quarter. Given his third consecutive start in Rondo’s absence, this stretch might be just what the Doc ordered in building Bradley’s confidence and expediting his development in what some believed could be a breakout season for the young guard.

WHAT WENT WRONG

No hands on deck: With Rajon Rondo (wrist), Ray Allen (ankle), Mickael Pietrus (shoulder), Keyon Dooling (knee) and Chris Wilcox (calf) all nursing injuries, the Celtics only had 10 active players on their roster. Hence, a starting guard combination of Avery Bradley and Sasha Pavlovic. Even with a full roster, the C’s should have had their hands full with the Magic, and you would have thought the lack of bodies might make it exponentially more difficult on an aging team still playing its way back into shape — but this win was a breakthrough for the Celtics.

Superman in the middle: The Celtics already struggle in the paint on both ends of the floor, and Dwight Howard doesn’t help matters. Howard scored the Magic’s first six points and nearly had a double-double by halftime (14 points, 8 rebounds). The C’s made the proper adjustments and “held” Howard to 18 points and 14 rebounds.

Tempers flare: Midway through the third quarter, with Jermaine O’Neal and Howard battling for position in the paint, the former waved his finger in the latter’s face as the two exchanged pleasantries. Both parties had to be separated and each was assessed a technical for the skirmish. O’Neal eventually fouled out of the game.