Westbrook scored 21 points while playing just 25 minutes and Durant added 20 during his 31 minutes of action. The Oklahoma City bench produced 41 points, led by 18 from Kevin Martin.
The Thunder took a 17-point lead into the fourth quarter to win their ninth home game in 10 attempts. They have captured three in a row overall.
John Wall led Washington with 18 points and 12 assists, but he made just 3-of-18 from the field. Wall had scored a career-best 47 points in his previous outing, a victory over Memphis on Monday.
Durant and Westbrook combined to go 20-of-21 from the foul line. Oklahoma City ran its home record this season to 32-5.