The Panthers scored on Jimmy Clausen's 79-yard throw to Lamont Bryant with 2:31 remaining and could have tied the contest by kicking the extra point.
Carolina chose to go for a 2-point conversion, however, and it failed when Clausen's throw to Bryant in the end zone fell incomplete.
Charlie Batch opened at quarterback for the Steelers and he completed 11-of-14 passes for 102 yards and a touchdown. Pittsburgh (3-1) will begin the season in Denver when Peyton Manning will make his debut for the Broncos.
Clausen was 9-of-19 for 173 yards and two touchdowns for the Panthers, who wound up 2-2 during the exhibition season and will begin its campaign on the road against Tampa Bay.