In a meeting of teams that have gotten off to good starts in the lockout-shortened season, the Senators halted the Canadiens' four-game winning streak. Ottawa has won five of its first seven games with one of its losses having come in overtime.
Jim O'Brien scored for Ottawa to forge a 1-1 tie after one period and the Senators then produced two power-play goals during the first half of the second stanza.
Alfredsson delivered the first one and Mika Zibanejad had the other less than 2 minutes later. It was the first goal of the season for both.
Anderson made 28 saves while Peter Budaj gave all five goals on 26 shots.