Anthony Mantha, Dylan Strome and Dowd scored in a 7:12 span in the second period to put Washington ahead. Dowd then sealed it with his second of the night and fourth of the season with 4:02 remaining in the third.
Philipp Kurashev had a goal and an assist, and Connor Murphy also scored for Chicago, which ended its first two-game win streak of the season. NHL rookie scoring leader Connor Bedard assisted on both Chicago goals, and Arvid Söderblom had 23 saves.
Kuemper gave the Capitals solid goaltending again after Charlie Lindgren shut down the Rangers in a 4-0 win at home on Saturday night.
Mantha, who has seven goals for the season, has four goals and two assists in his last seven games. Strome, a former Blackhawk, scored his 11th goal and has three in his last three games.
Chicago had the better chances in the scoreless first. During a flurry with about 7:30 left in the period, Kuemper came up with several tough saves, including one on a close-in shot by Lukas Reichel.
About a minute later, Kurashev kicked the puck into the net and the goal was immediately waved off.
Kurashev opened the scoring with a legit tap-in at 6:49 of the second from the edge of the crease. He converted Seth Jones’ cross-ice feed to cap a crisp passing play started by Bedard.
Mantha tied it on a breakaway 1:22 later. He got past the Chicago defense after taking Connor McMichael’s feed, then beat Söderblom with a sweeping backhander for this ninth goal.
McMichael, the Capitals' first-round draft pick in 2019, played his 100th game.
Strome put Chicago ahead 2-1 with 6:50 left in the period after T.J. Oshie knocked 6-foot-6 Chicago rookie defenseman Alex Vlasic off the puck behind the net with a big hit. Strome was open on the left side on the crease and directed in Joel Edmundson’s feed.
Dowd made 3-1 just 93 seconds later to cap a scrum at the net. Dowd had tried to jam in the puck from the pile-up, but it squirted free in front. Malenstyn shot it toward the net and Dowd was credited with knocking it over the goal line.
Set up by Malenstyn, Dowd made it 4-1 from the slot with 4:02 left in the third.
Murphy pinched in and converted Bedard's backhand cross-ice pass with 1:42 left to complete the scoring.
Capitals: At Philadelphia on Thursday night.
Blackhawks: At Edmonton on Tuesday night.
AP NHL: https://www.apnews.com/hub/NHL
Matt Carlson, The Associated Press