Capitals 4, Blackhawks 1
Corey Crawford had 32 saves for the Blackhawks (2-4-1).
Marian Hossa cur the Blackhawks' deficit in half less than a minute later when he knocked in his own rebound during a power play.
Chicago's Peter LeBlanc received a match penalty for a hit to the head of Capitals forward Alexander Semin at 12:37 of the third period. A slashing penalty on Hossa gave the Caps a 5-on-3 advantage, and Green beat Crawford with just over 3 minutes to play.
Jay Beagle added a short-handed, empty-net goal.
LeBlanc will likely be the next player suspended by new NHL disciplinarian Brendan Shanahan after he has an automatic hearing for his match penalty.
The Blackhawks will open the regular season Friday at Dallas. The Capitals (3-3-1) will host Carolina on Saturday.