Chris Neil, Jason Spezza and Chris Phillips also scored for the Senators, who snapped a two-game losing streak and won for only the second time in nine games. Daniel Briere and Thomas Vanek scored for the Sabres, who had their four-game winning streak snapped. Buffalo (15-2-1) lost for only the second time in regulation.
Schaefer deflected Daniel Alfredsson's wrist shot from the right point past goalie Martin Biron with 7:11 left in the third to give the Senators a 3-2 lead. The goal was upheld after a replay review showed he didn't strike the puck with a high stick.