Bradford hurled for 310 yards on 26-of-35 attempts -- mainly targeting Amendola, who made 15 catches and scored a touchdown as the Rams (1-1) snapped an eight-game losing streak dating to last season.
Brandon Gibson and Matthew Mulligan each hauled in a scoring strike, and Daryl Richardson rushed for 83 yards on 15 carries for St. Louis.
The Redskins (1-1) lost despite a good second pro game from first-round draft choice Robert Griffin III, who completed 20-for-29 passes for 206 yards, one touchdown and one interception.
Griffin also racked up 82 rushing yards on 11 carries.
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