After having their 12-game home winning streak snapped on Wednesday by Brooklyn, the Thunder broke things open in the third period against the 76ers.
Philadelphia is 2-5 on an eight-game road trip that concludes Saturday in San Antonio. The two wins came over Memphis and the Los Angeles Lakers.
Westbrook scored 27 points and Durant had six rebounds and three assists to go with his 26. Kevin Martin added 16 for the Thunder, while Serge Ibaka had 15 and 10 rebounds.
Philadelphia was led by Nick Young with 21 points. Jrue Holiday, who had a triple-double Wednesday in a loss to Phoenix, scored 15 points and had nine assists.
Oklahoma City shot 52 percent from the field and made 10-of-17 from beyond the 3-point arc.