Belinelli came off the bench to sink 6-of-8 field goals, including four 3-pointers on a night when the Spurs shot 53.7 percent from the field and 23-of-25 free throws.
Josh Smith led Detroit with 24 points and Andre Drummond scored 16. The Pistons shot a respectable 50 percent from the field but lost their third consecutive game.
The two teams played it close most of the way. San Antonio led 57-53 at halftime but extended their margin to as many as 15 points in the fourth quarter.
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