Durant scored just 21 points, eight below his season average, while playing only 31 minutes in the rout. He was one of five Oklahoma City players to reach double figures with Thabo Sefolosha adding 18 points and both Kentrick Perkins and Russell Westbrook scoring 17.
The Thunder hit 57 percent of their field goal attempts and went 14-of-21 from 3-point range. They led by just five at halftime, but then outscored the Suns 36-20 in the third period.
Oklahoma City has won three in a row after suffering through a 3-4 stretch.
Phoenix, which has lost six out of eight, was led by Michael Beasley with 25 points.