Washington's efforts keyed a stellar defense by Arizona (3-2), which forced four turnovers.
On the next series, Calais Campbell sacked Panthers quarterback Cam Newton in his own end zone for a safety for a six-point advantage.
Arizona picked off Newton three times and forced him to lose a fumble with 2:38 remaining, which led to a 7-yard TD pass from Palmer (19-of-28, 175 yards, three interceptions) to Jim Dray.
Newton completed 21-of-39 attempts for 308 yards but didn't record a TD for Carolina (1-3).
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