Oleg Petrov and Richard Zednik scored and Doug Gilmour had three assists for visiting Montreal.
Zednik gave Montreal a 3-1 lead 58 seconds into the third with his 19th goal, and Petrov capped the scoring at 6:09 with his 23rd. Gilmour, the team's assist leader, helped out on both scores.
Montreal, 2-0-2 in its past four, remains in the eighth and final playoff spot in the East but moved four points ahead of the Rangers and Sabres, who are tied for ninth.
Florida goalie Roberto Luongo left 6:50 into the game with an injury to his right ankle and was replaced by Trevor Kidd.