Durant, who also grabbed nine rebounds, was 14-of-20 from the field and 12- of-18 from the foul line while Westbrook tallied 13 points, 14 assists and 10 rebounds in the first three quarters.
"He is just so physically gifted and he is so competitive," Sixers head coach Brett Brown said of Westbrook. "There's an angry competitor that wills his way into doing stuff. And so you saw those physical abilities along with just such a strong mind, it's a powerful combination."
Reggie Jackson and Serge Ibaka added 14 points apiece for the Thunder, who have won three straight on the heels of their three-game skid. Ibaka also sat the entire fourth quarter with the win well in hand.
"I thought the defense was really active all night. We were getting in their passing lanes, did a good job of disrupting their offense," OKC head coach Scott Brooks said.
James Anderson provided 20 points to lead Philadelphia, which has dropped 15 in a row.
After Anderson hit a 3-pointer to get the Sixers within 12-9 less than four minutes in, Perry Jones and Durant nailed triples to cap a 10-0 run and give the Thunder a 22-9 lead a little before the midway point of the first.
OKC wasn't threatened again.
Durant netted 12 points and Westbrook dished out a team-record eight assists in the first quarter as the Thunder led 37-23 going into the second before heading into the break with a 61-45 advantage.
OKC took a 98-76 spread into the fourth, where it led by as many as 37 on the way to the easy win.
Oklahoma City shot 56.6 percent (43-of-76) from the floor ... The Thunder tallied 22 points on 18 Philadelphia turnovers and held a 57-38 advantage on the boards.