It happened again later in the quarter, when Rainey hauled in a punt at the Pittsburgh 9, made a defender grasp at thin air then dashed 91 yards for a score. That one came back too, thanks to another holding penalty.
Carolina used the reprieve to eventually tie the game. Derek Anderson struggled during his half of play — completing 8 of 18 passes for 91 yards — but did put together a 17-play, 73-yard drive that ended with Medlock's 31-yard field goal.
It was the highlight of the night for Medlock, who beat out veteran Olindo Mare for the starting job earlier in the week. He had the distance on a 56-yard field goal attempt in the third quarter, but it sailed wide right and his game-winning attempt sailed wide left.
The Panthers tied it at 10 early in the second half when Clausen found Jared Green for a 3-yard touchdown pass.
Pittsburgh reclaimed the lead early in the fourth quarter when Batch found tight end Weslye Saunders for a 6-yard score.
The Steelers did allow a handful of starters to break a sweat, including nose tackle Casey Hampton. The 12-year veteran spent the first three weeks of training camp on the physically unable to perform list while recovering from offseason knee surgery. Still, Hampton vowed to be ready for the opener and he sprinted onto the field when he was introduced.
The five-time Pro Bowl selection played throughout the first quarter and finished with two tackles.
"I didn't want to go into Denver without having any full-speed action," Hampton said.
NOTES: Pittsburgh rookie LB Sean Spence, the team's third-round pick in the NFL draft, was taken off the field on a cart with a left knee injury in the third quarter ... Pittsburgh WR Mike Wallace, who signed his one-year tender on Tuesday, did not dress for the Steelers. Wallace will become eligible to start practice on Friday, though the Steelers don't return to the practice field until next week ... Carolina LB Jon Beason did not play again. Beason has been dealing with a hamstring injury throughout camp ... Both teams open the season on Sept. 9, when the Steelers play in Denver and the Panthers visit Tampa Bay.