Harley gave the Stars a 2-1 lead at 11:07 with a shot through traffic from between the face-off circles.
Rasmus Sandin tied it 2-2 at 6:24 in the second period with a shot past Oettinger’s glove from the point.
“There are 60 minutes of hockey, and we didn’t play 60 minutes of great hockey,” Sandin said. “I think there are moments where we played pretty good, but too often and too much time of today where it’s not good enough, I think.”
Marchment gave the Stars a 3-2 lead at 11:00, tapping the puck five-hole from the top of the crease on the power play.
Duchene extended the lead to 4-2 at 2:24 in the third period when he beat Lindgren with a wrist shot off a drop pass from Marchment in the slot.
“This team is so easy to play with, everyone is so good and we’re so well coached,” Duchene said. “You just throw on the gear and go out there and take care of your business and you have success. It’s been a lot of fun so far. I’m really grateful to be a Dallas Star.”
NOTES: Harley tied Seguin (three in 2019-20) and John Klingberg (three in 2015-16) for the most overtime goals scored by a Stars/North Stars player in a single season. He is tied for fifth most goals by a defenseman this season (11). Rasmus Dahlin of the Buffalo Sabres (13) leads the NHL. … Strome has four goals in the past five games. ... Capitals forward Max Pacioretty left the game with a lower-body injury and did not return. According to Washington, the injury is not related to his recent Achilles issues.