Durant tied a career playoff high with 41 points and added 14 rebounds.
Serge Ibaka had 17 points, 11 rebounds and two blocks.
Second-year player Reggie Jackson — Westbrook's replacement who was playing in just his third career postseason game — had 14 points and single-handedly sealed the victory by converting two free throws with 8.0 seconds left and soaring high for the game's final rebound as the buzzer sounded.
Thunder sixth man Kevin Martin wasn't half-bad, scoring 12 points and shooting 3 for 5 from the field in the first half.
After intermission, however, Martin struggled mightily, going scoreless in 15 minutes of playing time while shooting 0 for 6 from the field.
Martin knew he needed to pick up the slack for Westbrook by hoisting more shots alongside Durant.
“We're definitely going to take more shots,” Martin said of himself and Durant. “I think that part's simple.
“The complicated part is we've got to make more shots because Russell is such a big part of what we do at both ends of the court.”
Derek Fisher, who refused to play for the Rockets after being traded to Houston last season, had nine points that included two free throws with 12.5 seconds left to give OKC a 102-99 lead.