Norfolk took the first game of its Calder Cup playoff series against Wilkes-Barre/Scranton on Friday, 5-2.
The game was knotted at 2-all after the second period, but the Admirals scored three times in the third to take the victory.
Stephen Dixon and Kyle Brodziak both scored for the Penguins, who welcome the Admirals for Game 2 on Saturday night.
The series shifts to Norfolk for the next three games. It returns to Wilkes-Barre/Scranton for Games 6 and 7 (if necessary).