When was the last time the Washington Redskins beat the Pittsburgh Steelers?

I do believe the last time the Redskins beat the Steelers was in the 1991 season. The score was 41 to 14.

08/26/2005 - PIT 10 @WAS 17 (pre-season)

it was in the 2009 preaseson

i believe it was yesterday December 13th