The 23-year-old replaced the suspended Franz Burgmeier, who is likely to return at home to Grimsby Town on Saturday, but Penney was happy with Tremarco.
"After Carl hadn't played for so long he was never going to play the full 90 minutes, especially in a game like Tuesday's, so he came off in the second half," he told the Darlington and Stockton Times.
"But he's naturally left footed and I thought he gave us balance on the left. Him and Ryan Valentine looked after Bradford's Steve Jones, who was eventually subbed.
"Then Carl helped keep Joe Colbeck quiet as well, and on the other side of the pitch Neil Austin did very well against Omar Daley."