The Knicks were led by five-time all-star Carmelo Anthony who top scored with 31 points and bench man J.R. Smith who added 22, nine of them during a third quarter surge in which the home team broke clear.
This is the first time since the 1993-94 season the Knicks have started perfect through four games, halting a three-game winning streak for the Mavericks who dropped to 4-2.
"I thought (in) the second half, we kind of settled in and our defense began to click a little bit," Knicks coach Mike Woodson said.
"We held them to 37 points in the second half and we've had four straight games where no one has scored 40 points in the second half, so that's locking in and taking pride in defending the ball."
It was just the fourth loss in the last 22 meetings against the Knicks for Dallas, who missed injured stars Dirk Nowitzki and Shawn Marion.
O.J. Mayo top scored for the Mavericks with 23 but had eight turnovers in a mixed night.
Knicks players Jason Kidd and Tyson Chandler played important support roles in the win against their former team with Chandler adding 11 points with nine rebounds.
Kidd enjoyed the victory but refused to get overly personal.
"No matter who our opponent was tonight, we needed to come out, get a 'W' and keep this thing going," he said.
"We were a little flat to start the game, but Dallas is laying extremely well, so we knew we would have our hands full."
The Los Angeles Lakers responded to the axing of coach Mike Brown by belting the Golden State Warriors 101-77 at the Staples Center for their second win of the season.
After a close first quarter, the Lakers went on a tear with Kobe Bryant scoring 27 points, much to the delight of the home crowd.
Having fired Brown earlier in the day after starting the season 1-4 and losing all eight pre-season exhibition games, the Lakers displayed new vigour and style under interim coach Bernie Bickerstaff.
The home fans, however, made no secret of who they wanted to fill the vacant position, chanting "We want Phil" throughout the night in reference to former coach Phil Jackson who helped the Lakers to five of their 16 championships.
Bryant claimed the side still used a little of the "Princeton" style offence Brown was trying to implement in the side before his dismissal but admitted instinctual play was the real help.
"We just had to focus on our execution. It was about coming out and playing hard," Bryant told reporters.
"We really just went out there and played almost like a pick-up game.
"We opened up the floor and when we had the opportunity we actually ran some of the Princeton stuff in terms of flair picks and back picks and things of that nature but we really just tried to read each other and react."
Pau Gasol stepped up for the home side in support of Bryant's scoring efforts, pulling in 16 rebounds and scoring 14 while bench man Jordan Hill contributed 14 points also.
"Pau was fantastic," Bryant said.
"He played with the type of intensity we're accustomed to seeing from Pau. The important thing is he needs to keep up that intensity.
"He's so talented he can come out and coast to a 20 points and rebound game but we need this intensity."
The Warriors dropped to 3-3 with the loss.