Durant and Westbrook combined for 23 points in the third quarter as Oklahoma City extended a 46-45 halftime lead to 82-75. Westbrook had two 3-pointers, a driving basket and three of his 12 assists in the final six minutes, turning a 60-all tie into an 82-72 lead before a late 3-pointer by Wesley Johnson.
Thunder reserves widened the advantage in the final period helped by strong play from center Cole Aldrich, who is battling for the reserve center spot behind Kendrick Perkins. Aldrich finished with 12 points and six rebounds, scoring 10 in the fourth quarter.
Serge Ibaka, playing the first and third quarters with the starters, had 13 points and eight rebounds.
Johnson had 15 points, PJ Tucker 11 and Solomon Jones 10 points and 10 rebounds for Phoenix, which played 15 players.
The Thunder rested five players with various injuries, including starters Perkins and Thabo Sefolosha. Also out were sixth man James Harden with a groin pull, reserve center Daniel Orton and top draft pick Perry Jones (tender knee).
Durant and Westbrook combined for 14 points and staked Oklahoma City to a 24-18 lead before taking a seat at the start of the second quarter. The two returned for the final four minutes of the half and Westbrook hit an off-balance 3-pointer at the buzzer to give the Thunder a 46-45 halftime lead.
DeAndre Liggins started in place of Sefolosha and ignited the crowd in the third quarter with a dive that knocked the ball loose, picked up by Westbrook and fed ahead to Ibaka for a dunk that pushed the Thunder lead to 77-66.
Hasheem Thabeet started at center for Oklahoma City. He had five points and four rebounds, and got in an altercation with Jermaine O'Neal in the second quarter. The two were separated and both hit with technical fouls.