PLAYER OF THE GAME: Robin Lehner stopped 38 of the 40 shots he faced on the night, including 16 first-period shots.
STAT OF THE NIGHT: Kirby Dach tied a season-high five-game point streak with an assist on DeBrincat's opening goal.
UP NEXT: The Blackhawks embark on a five-game swing through Western Canada beginning on Sunday night in Winnipeg.
For the second straight night, the opening period ended scoreless thanks in large part to the Blackhawks netminder. Robin Lehner made 16 saves in the opening 20 minutes, including a diving glove save to deny David Krejci at the 18:09 mark.
Chicago struck first in the middle frame, snapping an 0-for-8 power play skid and a five-game goalless drought for DeBrincat. As Krejci sat for boarding Adam Boqvist (who would not return, right shoulder), Patrick Kane put a puck into the slot that Dach drove to the net before DeBrincat put home the rebound at the side of the crease for a 1-0 lead at the 6:50 mark of the second.
The Bruins would answer as Sean Kuraly skated out from behind the Blackhawks net and fired a shot from the bottom of the circle that deflected between Robin Lehner's pads and into the goal at 12:49 of the second.
For the second straight game, 60 minutes would not be enough, despite a late would-be go-ahead tally from Drake Caggiula that was called back when the referees deemed the puck to be played with a hand pass.
In overtime, Charlie McAvoy scored the winner off the rush, sealing a 2-1 win for the Bruins.