Alex Ovechkin had a goal and two assists while Tom Wilson and Andre Burakovsky each scored. Wilson now has seven goals in the nine games he's played this season. This also was his 400th career game.
But he did not get to stick around for the finish of it. Wilson was ejected when he received a match penalty late in the second period after clipping Brett Seney in what appeared to be the shoulder/neck area on the blindside while skating past him, leaving the Devil on the ice and dazed.
Michal Kempny added two assists in the win. Goalie Braden Holtby finished with 33 saves as the Capitals scored four in the third period to break open a one-goal game.
Backstrom gave Washington a 1-0 lead in the first period when Ovechkin found him in the slot and Backstrom beat goalie Keith Kinkaid at 3:51.
Wilson then made it 2-0 with a shorthanded goal eight seconds into the second period. New Jersey cut the lead to 2-1 on its own shorthanded goal at 9:23 of the period. Blake Coleman came in on a rush and took a shot that Holtby stopped, but Travis Zajac scored on the rebound.
Burakovsky split two New Jersey defensemen and scored 5:45 into the third period to extend the Caps' lead. Backstrom made it 4-1 on a power-play goal when the Capitals had a two-man advantage midway through the period.
One of the penalties was the rare call of butt-ending against Travis Wood. Evgeny Kuznetsov got an assist on the play in his first game back after missing six with what's believed to be a concussion.
Nico Hischier and Marcus Johansson then scored for the Devils to make it 4-3 with 1:50 left, but Ovechkin answered with an empty-net goal and fed Backstrom to finish off his hat trick.
(With inputs from agencies.)