The C's 18-game winning streak is the longest since Houston's 22-game run last season. The win also helped Boston match the best 28-game start in NBA history, equaling the 1966-67 Philadelphia 76ers and the 1969-70 Knicks, both of which started 26-2 en route to NBA championships.
Ray Allen and Paul Pierce scored 18 and 17, respectively, for the Celtics, who will attempt to set the franchise record for consecutive wins on Tuesday against the 76ers. Kendrick Perkins had 12 points and 12 boards in the win.
Quentin Richardson poured in a game-high 29 points for the Knicks, who have dropped four straight. Nate Robinson added 23 points and Chris Duhon 20 and 10 helpers in defeat.
The Celtics jumped out to a 40-21 lead after the first stanza but the Knicks cut it to 66-58 at the half.
Threes from Richardson and Al Harrington, followed by a layup from Tim Thomas brought the Knicks within 89-83 late in the third.
However, the Celtics kept pushing and went into the fourth ahead 98-87.
Two Allen baskets, a Brian Scalabrine three and two Leon Powe layups gave the home team a 109-89 lead with 8:37 left in the game.
A David Lee layup brought New York within 113-101 with about 4 1/2 minutes left, but Boston pulled away late to seal the victory.