Pascal Leclaire sparkled in goal for Ottawa, stopping 24-of-25 shots through two periods before being replaced by Brian Elliott due to an unspecified injury Leclaire apparently suffered when he did the splits on a breakaway in the second period.
Elliott made 14 saves in the final 20 minutes and was credited with the win.
Thomas Vanek, Patrick Kaleta and Jason Pominville scored for the Sabres. Patrick Lalime allowed all five Ottawa goals on 26 shots.
Alfredsson scored at 8:14 of the second period to put Ottawa ahead 2-1. His second goal made it 5-1 at 8:00 of the third period.