Things started out well for Buffalo as Montour scored twice early to put Buffalo ahead 2-0.
Montour jumped into the play, pounced on a loose puck in front and potted his fourth goal of the season 2:14 into the contest. And then with 9:48 remaining in the opening period, he one-timed a pass from Rasmus Ristolainen at the left point past Anderson.
Then in 3:29, the Senators scored four goals to take a two-goal lead.
With 5:58 left in the first, Vladislav Namestnikov scored his fourth shorthanded goal of the season, cutting in and seeing his wrist shot sneak in past Hutton. Then with 4:53 left, Artem Animisov scored his first goal, as he avoided Hutton's poke check to dance in from around the back of the net to put the puck home.
Then on the ensuing faceoff, Drake Batherson knocked in his own rebound with 4:44 remaining it make it 3-2. And with 2:29 to go in the first, Animisov put Ottawa ahead by a pair when his long wrist shot by Animisov beat Hutton high
The Sabres came out of the gates strong in the second period when Okposo scored his second goal in as many games when he drove hard to the net and knocked in a feed from Johan Larsson at the 2:36 mark.
At the 9:00 mark, Jean-Gabriel Pageau was credited with a goal after a rebound deflected in off him as he crashed the net.
Olofsson one-timed a shot on the power play in with 6:13 left in the second to put Buffalo back within distance.
Ottawa, however, outscored Buffalo 2-0 in the third. With 7:07 remaining in the final period, Pageau's power play one-timer found the back of the net to give the Senators a 6-4 lead.
On the power play with just over two minutes to play, the Sabres pulled Hutton to try their hand at a 6-on-4 man advantage. However, Anthony Duclair scored on the empty net for Ottawa's second shorthanded goal of the night.