Durant connected on 15-of-30 shots from the field while Westbrook provided eight rebounds and five assists as the Thunder reeled off their fourth straight win.
Kevin Martin came off the bench to net 12 points for Oklahoma City, which grabbed control of the contest with a 15-3 run in the second quarter.
The Suns, meanwhile, lost for the sixth time in seven games despite 21 points from Shannon Brown.
Marcin Gortat donated a double-double of 19 points and 15 boards in the setback.
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