"We were a little upset and we transferred that energy the right way actually," Weber said. "It was a good reaction. I think guys were really obviously upset and I thought we deserved a goal there, but we did the right things and we came back and played the right way after that."
Byron made it 4-2 at 13:37, and Drouin extended the lead to 5-2 with an empty-net goal at 17:31.
Matthew Peca scored for the second straight game to give Montreal a 1-0 lead at 3:39 of the first period.
White scored 20 seconds later to tie it 1-1 on a rebound in the crease. Julien challenged the play for goaltender interference, but the call was upheld after a video review.
Boedker gave the Senators a 2-1 lead at 9:11 of the second period on a shot from the slot.
"In the first period, we came out real good, a solid first period, and you could see it fade away slowly in the second period and you could see the energy go down," Senators coach Guy Boucher said. "And in the third period, we just didn't have enough to follow them, plain and simple.
"The circumstances were as bad as you can imagine. It was a long road trip, the last game, back-to-back, they're not on a back-to-back, so we would have needed a bigger lead going into the third period, but we didn't have it and we couldn't keep up with their speed by the third period."