The Panthers and Sabres played an early-season, home-and-home series with Carolina winning both contests.
Alexander Semin answered for the Panthers less than 2 minutes later and overtime was looming when Harrison scored the winning goal. Harrison also assisted on Jeff Skinner's empty-net tally with 26 seconds to play.
Ellis made 40 saves in his first start of the season. Ryan Miller stopped 39 shots for the Sabres, who lost to Carolina 6-3 on Thursday. Both teams emerged with 2-2 records.