Evan Turner had his first career triple-double with 10 points, 12 rebounds and 10 assists and Boston pulled away with 20 unanswered points in the second half and extended New York's losing streak to eight with a 115-94 win on Wednesday night.
Isaiah Thomas scored 19 in his home debut for the Celtics.
Jae Crowder finished with 18 points, hitting a pair of Boston's eight 3-pointers in the fourth quarter. The Celtics outscored the Knicks 35-22 in the final period and 77-45 in the second half.
Jonas Jerebko added 20 points, Marcus Smart scored 16 and Avery Bradley finished with 12 points for the Celtics. Thomas, acquired by Boston on Feb. 19 in a deal with Phoenix, hit all 11 of his free throws and added seven assists and six rebounds.
Andrea Bargnani led New York with 17 points. Lou Amundson, Jason Smith and Langston Galloway scored 14 points each for the reeling Knicks.
Amundson gave the Knicks a 68-62 edge midway through the third quarter, tying their largest lead of the game, then New York's offense stalled and never recovered as the Celtics starting hitting from outside.
Boston scored the last nine points of the third quarter and first 11 of the fourth.
The Celtics closed the third quarter on a 16-3 run, scoring the last nine points of the period and taking an 80-72 lead into the fourth. Smart opened the fourth with back-to-back 3-pointers and New York called timeout trailing 86-72.
The delay did nothing to spark the Knicks or slow down the Celtics, who added another 3-pointer by Crowder and two free throws by Jerebko for a 91-72 lead.
Amundson ended New York's drought on a jumper with 9:03 left to play. It was the first points for the Knicks since Bargnani's jumper with 2:59 left in the third put New York up for the last time at 72-71.
Knicks: Tim Hardaway started at forward for Cleanthony Early (ankle), who was still available and came off the bench. G Shane Larkin (illness) and F Lance Thomas (groin) did not play. First-year coach Derek Fisher and the Knicks have been stuck on 10 wins since beating the Los Angeles Lakers 92-80 on Feb. 1. After shooting 52 percent in the first quarter, the Knicks were just 5 for 19 in the second.
Celtics: F Kelly Olynyk missed his 15th straight game with a sprained right ankle. Coach Brad Stevens said Olynyk should be ready to return within a week. ... Thomas, Luigi Datome and Jerebko played their first home games with the Celtics.
Knicks: Visit Detroit on Friday.
Celtics: Host Charlotte on Friday.