Boston clawed their way back from a 2-1 deficit to start the third period, with David Pastrnak, Charlie McAvoy and Pavel Zacha combining for a beautiful overtime winner.
Not only did Montgomery get a win over the first NHL team he had a head coaching job for, but he also accomplished an incredible personal milestone.
2022-23 has been a historic season for Boston, so far, which has helped Montgomery reach 100 wins. He's been successful throughout his NHL career, too, as he holds a 100-51-15 record all time.