Green added two assists and Nicklas Backstrom contributed a goal and an assist for the Capitals, who got scores from Green and Marcus Johansson only 61 seconds apart late in the first period to set the tone.
Joel Ward chipped a third-period tally and Tomas Vokun turned aside 32-of-33 shots as Washington routed the Red Wings and emerged as the NHL's only unbeaten squad at 7-0-0.
Niklas Kronwall got Detroit's only tally and Ty Conklin was blitzed for seven goals on 25 shots.
The Red Wings fell short in their bid to tie the 1972-73 team as the only squad in Detroit history to start the season with six straight wins.
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