Irving recorded his 15th game with at least 20 points and led Boston in scoring for the 13th time. Irving's showing helped the Celtics win for the fifth time in six games since a 117-109 home loss to New York on November 21 in a game Boston trailed by 26 at one point.
Irving shot 9-of-15 and hit three-pointers as the Celtics matched a season-best by shooting 53.3 per cent and reached 120 points for the fourth time. The Celtics also scored at least 115 points in four straight games for the first time since December 1990.
Irving ended the game wearing an ice wrap on his right shoulder as the Celtics set a season high in points and in assists with 32.
Jaylen Brown added a season-best 21 and shot 7-of-10 after sitting out the last three games with a back injury. Al Horford added 19 and a season-high 12 rebounds while Jayson Tatum contributed 17 for the Celtics.
Tim Hardaway Jr scored 22 points for the Knicks, who lost their second straight since an overtime win over Milwaukee on Saturday. Emmanuel Mudiay added 17 and Enes Kanter contributed 14 as the Knicks shot 39.6 per cent.
The Celtics shot 55.1 per cent in the first half and took a 69-58 lead by half-time.
The Knicks were within 43-40 on a three-pointer by rookie Kevin Knox with about nine-and-a-half minutes left but Terry Rozier hit two three-pointers in a 10-4 run.
New York came within five points three times in the final four-and-a-half minutes but Horford had two dunks and scored Boston's last 11 points of the half.
The Knicks closed to 89-82 on a three-pointer by Hardaway with 3:49 left in the third quarter but Irving and Gordon Hayward hit threes as Boston finished the third with a 10-2 run to take a 99-84 lead into the fourth.
Sky Sports is the new home of the NBA in the UK with live coverage throughout the week, including selected live games free to all Sky subscribers via Sky Sports Mix.