The Pirates are still in the bottom four and without a victory in 12 league games following a turgid stalemate at the Memorial Stadium.
But Penney, who is still without a win since taking charge eight days ago, said: "To come away from this game with a clean sheet was a massive thing for me. This team hasn't managed to keep one since October, so to finally get one was vital and it will give the players a lot of confidence going forward.
"It looks like they`ve forgotten how to win, but the important thing for us was to make sure that we saw the game out without losing.
"I know we have players who can play, but there is no point producing pretty football and then getting beat every week.
"It's not going to be pretty for the foreseeable future because we are going to have to battle and grind our way out of the position we are in. A clean sheet and a more solid-looking performance gives us something to build on, though, and now we hope we can add some goals to that."