Moore blocked a punt and had four tackles -- one for a loss -- one quarterback hit and a couple of pressures. He also disrupted short passes to running backs.
"Moore obviously was a problem for Pittsburgh," coach Tom Coughlin said. "He keeps coming and he likes it."
Damontre Moore doesn't turn 21 until next month.
The Giants drafted Moore in the third round from Texas A&M, at which he had 26.5 sacks in three seasons. But Coughlin said Moore needed to improve his work habits during the week leading up to games. Considering that he's only 20, Moore figured to be more of a prospect for the near future than a rookie who could come in and make an instant impact.
But thus far, Moore has shown he could be more than just a prospect to develop. He was a presence with his speed, which was on display when he exploded out of nowhere and made a leaping block on a fourth-and-29 punt at the Steelers' 17 with 11:27 to go in the first quarter.
Louis Murphy recovered the punt and got the Giants to the Pittsburgh 5-yard line. Though the Giants had to settle for a field goal, Moore had already made a monster play that only seemed fitting for a player nicknamed "DaMonster" in college.
"I just ran in and got a little hitch step and I was there to make a play," Moore said. "It was all surprising to me. I'm just glad Coach put me in a great situation."
When the Giants drafted Moore, they figured his quickest way toward being active on game days would be on special teams. But Moore showed he can potentially be a factor in the pass-rushing rotation. After Jason Pierre-Paul, Justin Tuck and Mathias Kiwanuka, the Giants need a fourth pass-rusher to step up. They have used tackle Cullen Jenkins at defensive end, but Adrian Tracy and Moore are competing to be a part of the rotation.
Tuck raved about Moore's potential last week. Moore might be ready to contribute this season.
"I feel like it was all right," Moore said of his performance. "There is always room for improvement. I made a lot of mistakes out there. I'm just ready to watch some film and get better."