The Blackhawks went out to a 4-0 lead and held on despite the Senators responding by scoring three straight goals in the second period.
Defenseman Louis Crevier had a goal and an assist, Andre Burakovsky and Nick Foligno each had two assists, and Spencer Knight made 21 saves for the Blackhawks (5-3-2).
Tim Stutzle had a goal and an assist, and Drake Batherson had two assists for the Senators (5-5-1), who were playing the second of back-to-back games. Linus Ullmark made 19 saves. Ottawa had its three-game winning streak ended.
Colton Dach’s first goal of the season gave the Blackhawks a 1-0 lead at 6:47 of the first period. Dach picked up the rebound of a shot from the right point by Crevier and scored on the forehand from the bottom of the left face-off circle. With the initial pass to Crevier, Foligno recorded his 600th career point with the secondary assist on the goal.
Crevier made it 2-0 at 12:06 when he picked up the puck along the right-wing boards outside the right circle and one-timed the puck, which deflected into the net off the leg of Senators defenseman Nikolas Matinpalo.
A power-play goal by Bedard at 17:53 gave Chicago a 3-0 lead. Burakovsky skated to the goal line from the left point and made a cross-ice pass to Bedard, who scored with a wrist shot from the right circle.
Bedard put the Blackhawks up 4-0 at 2:58 of the second period. He moved into the offensive zone, made a toe-drag move and scored on a wrist shot from the slot.
Jake Sanderson got the Senators on the board at 4:58 with a shot from the blue line that caromed off the end board and went in off Knight.
Michael Amadio cut the Blackhawks’ lead to 4-2 at 7:09 when he skated out from behind the net and lifted the puck over Knight.
The Senators came within one at 8:31 when Stutzle moved into the offensive zone and scored with a wrist shot from the right circle that beat Knight glove side. Stutzle’s goal marked the Senator’s third in 3:33.
Bedard achieved the hat trick at 3:46 of the third period. Ryan Greene won a face-off, Bedard picked up the puck ant put it in with a snap shot from the left circle.