The Suns played their third road contest in four days and took on the Pistons 24 hours after falling by three points in Philadelphia. Phoenix has games remaining against Toronto, New York and Memphis on its current trip.
Phoenix ran out of gas in the second half while being outscored 62-33.
Detroit hit 52 percent of its shots from the field and made 12-of-16 from 3-point range. Villanueva made four of the long-range shots and Knight had three.
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