Mittelstadt poked in a rebound of a Dylan Cozens shot at the right of net. It was the final call for Buffalo broadcaster Rick Jeanneret, who is retiring after 51 seasons.
"It's a good way to end the year, I think," Mittelstadt said. "Obviously, there's been some ups and downs for everyone. It's a great way to end the year, a great way to end it for 'RJ'. Me and 'Cozey' we were talking, we're pretty proud to be his last call."
Owen Power and Tage Thompson scored for the Sabres (32-39-11), who ended the season with five wins in six games. Dustin Tokarski made 19 saves.
"It was tough at the beginning and obviously I think we fought a little bit after being sloppy at times, but not every game is going to be pretty," Thompson said. "Good teams find a way to win and we just fed off the energy of the crowd and each other on the bench. I don't think there was anyone that didn't think we were going to come back and win that game. That just shows the type of character we have in this group."