Brad Marchand scored at 3:37 of overtime as the Boston Bruins improved to 4-1-0 without captain Zdeno Chara in the lineup.
Patrice Bergeron had the other Bruins goal.
Jussi Jokinen had the lone Panthers goal.
Tuukka Rask made 18 saves in the win while Roberto Luongo stopped 23 shots in the loss.