Durant had 29 points, seven rebounds and six assists in 32 minutes. He made 10 of his 16 shots and added two steals.
Westbrook finished with a triple-double (14 points, 13 rebounds, 10 assists), and Serge Ibaka had 24 points on 10-for-14 shooting.
The Knicks (9-19) fell to 4-11 at home. They lost a total of 10 games at home last season.
J.R. struggles: With Anthony out, Mike Woodson decided to put the ball in J.R. Smith's hands. But last season's Sixth Man Award winner didn't deliver.
Smith forced shots for much of the afternoon and didn't make many.
He finished with 20 points on 8-for-22 shooting and missed six of his nine 3-point attempts. The Knicks were outscored by 32 when Smith was on the floor. He heard boos from the home crowd in the second half.
Iman Shumpert, the Knicks' other shooting guard, played with high energy. He finished with eight points, seven rebounds, four assists and two steals. Westbrook and the Thunder established a double-digit lead in the second quarter after Shumpert went to the bench with two quick fouls.
Orange equals awful: The Knicks are 0-7 in orange uniforms this season. They are 0-6 in their alternate orange jerseys. On Wednesday, they wore orange jerseys with short sleeves as part of a bizarre leaguewide dress code for Christmas Day participants.
Poor D: The Knicks allowed Oklahoma City to shoot 54 percent from the floor and 54 percent from beyond the arc. Things got so bad in the second half that a pocket of fans in the upper deck began to chant "Fire Woodson" as the Thunder's lead ballooned to 30 points.
Amar'e strong: One positive for the Knicks? Amar'e Stoudemire played well. The power forward finished with 22 points on 10-for-16 shooting. Andrea Bargnani struggled once again, scoring just nine points ... Chris Smith, J.R. Smith's younger brother, made his NBA debut with the Knicks down 26 and 1:41 to play.
What's next: The Knicks will practice on Thursday to prepare for a back-to-back with Toronto beginning on Friday. It's fair to wonder whether the embattled Woodson will be coaching the team at that point.