David Pastrnak scored on a one-timer off a cross-ice feed from from Taylor Hall at 2:42 of overtime for a 3-2 in over the Ottawa Senators.
Jake DeBrusk and Brandon Carlo scored for the Bruins in regulation (28-17-4) who snapped a two-game losing streak. Jeremy Swayman made 29 saves.
Tim Stutzle and Nick Holden also tallied for the Senators (18-25-5), who got a 30-save performance from Anton Forsberg in defeat.
Tyler Ennis almost tied the game for the Senators in the sixth minute of the third period, but while on the power play and an empty net staring him in the face, Ennis hit the post and seconds later, Swayman made a glove save off Ennis.
Eventually, Holden did tie the game for Ottawa as his shot from the slot beat Swayman with a crowd in front at 16:06 of the third to force overtime.
The Senators got off to a much better start then one week earlier when they were outshot 22-8 in the first period by the Bruins, who scored 45 seconds into the game. In the first period Saturday, the Senators were again unable to score, but neither were the Bruins and the shots were a much more respectable 11-9 in favour of Boston.
The Bruins eventually opened the scoring at 2:37 of the second period when DeBrusk backhanded the puck out of midair and put a one-hopper past Forsberg for a 1-0 lead.
The Senators got that one back just over four minutes later as Stutzle collected a rebound off an Artem Zub point shot that was tipped by Austin Watson and had an empty net to shoot at with Swayman out of position.
Later in the period the Senators had three great scoring chances as they kept the puck in the Bruins end for almost the entirety of a two minute four-on-four. Stutzle, Brady Tkachuk and Nick Paul all nearly gave the Senators the lead during that stretch but were unable to beat Swayman.
Brando Carlo, who was a game-time decision after cutting his wrist in the morning skate, gave the Bruins a 2-1 lead with just over a minute to play in the period. Forsberg dove out to try and cover the puck at the top of the crease but pushed the puck right onto the stick of Carlo who had an empty net to shoot at.