Kevin Garnett scored 16 points and grabbed 18 rebounds, and Jeff Green scored 18 points on just eight shots to lead the way.
Meanwhile, the Knicks suffered on offense, as Carmelo Anthony went 8-of-24 and J.R. Smith went 3-of-14.
Bradley began the game throwing one of the worst entry passes you'll ever seen an NBA player make, chucking the ball over Kevin Garnett's head and out of bounds.
It went downhill from there on offense until Doc Rivers appeared to lose trust in him, instead going to Terrence Williams at point guard.
Felton was arguably New York's best offensive player in the first half, scoring nine points and getting to the basket at will.
He began the third quarter getting wherever he wanted in the pick-and-roll with Chandler, scoring whenever he wanted because Boston's roll defender had to respect the pass.
He finished with 21 points in 44 minutes.
Pierce shot 0-of-6 in the first quarter, continuing to struggle badly in matchups at the foul line against Ray Felton and Pablo Prigioni.
In the second quarter, he hit a couple big threes that prevented the Knicks from mounting a big lead, but still struggled in those isolation situations.
He scored 16 points in 44 minutes and turned it over five times.
Prigioni knocked down his first shot, a three-pointer from the left wing, but passed up an open layup a few minutes later.
In 13 minutes that's about all he did.
Green was the first Celtic to reach 30 minutes of playing time, but he wasn't nearly as aggressive as he needed to be in nearly all of them.
Boston's strategy was to push the ball after New York's misses, but Green couldn't get going. In the fourth he threw down a vicious dunk in traffic to give his team a 15-point lead.
He then hit two huge corner threes with time winding down in the fourth quarter.
After beginning the game with a turnover and a layup, Shumpert took a seat as J.R. Smith replaced him. But in the second half he scored a few key baskets, including a difficult turnaround jump hook over Kevin Garnett's fingertips.
He finished with 12 points and six rebounds.
Bass scored nine of Boston's first 11 points, keeping the team in a game that was looking to be a blowout from the opening tip.
His defense, then, on Anthony in the first half was stable and consistent. Bass finished with 17 points in 40 huge minutes.
Anthony's shot was on early, as it typically is. He knocked down a series of tough, contested pull-up jumpers in the first quarter. But there were too many isolation plays in the first half, where he finished 6-of-14 for 14 points.
In the second half it was more of the same, with Anthony taking jumper after jumper, and missing a ton of them. He scored 22 points but needed 24 shots.
Garnett started the game slow, missing his only two first-quarter shots, but in the second quarter Boston went to him in the post to get its offense going and it worked.
He put both Kenyon Martin and Tyson Chandler in foul trouble, drew double-teams and found teammates behind the three-point line.
Garnett headed into halftime with 10 points and nine rebounds.
He finished with 18 rebounds and 16 points in what was one of the most courageous performances of his Celtics career.
Chandler picked up two early fouls, but after re-entering the game in the second quarter he began to show some life on the offensive end.
He grabbed an offensive rebound that led to a Carmelo Anthony jumper from the right corner, and finished an alley-oop lob immediately after the Celtics took their first lead of the game.
Terry went 2-of-7 in the first half, but knocked down a big three right before halftime.
In the second half he was huge, controlling ball-handling duties for key stretches of the fourth quarter and finishing with 17 points in 35 minutes.
Heading into his first game back after suspension, Smith went 0-of-5 in the first half, missing a few open jumpers and some tough contested shots at the rim.
It ended as Smith's worst performance in months, as he missed bad shot after bad shot and finished with 14 points on 14 shots.
Terrence Williams came out of nowhere to play huge point guard minutes, finishing the game with 17 big minutes and four points.
He was the only member of Boston's bench to get any burn, apart from Terry.
Jason Kidd scored zero points, missing all four of his shots, and Kenyon Martin was a foul machine in 13 minutes of action, hacking Boston five times.
Steve Novak played momentarily and knocked down a step-in jumper, but had to leave with back spasms.