David Trezeguet had given the Bianconeri a first half lead, but in stoppages Martins Adailton snatched the equaliser.
"At times we were too open and didn't track back as quickly or effectively as we were supposed to," continued Ferrara.
"Juventus are a team that try to attack at all times, but clearly we need to improve in defence. We also don't make the most of it when we're in possession, as we can be too frenetic."
Gianluigi Buffon performed more heroics before the last-gasp goal and the Coach admits his goalkeeper is over-worked.
"We must try to make life easier for him by making sure there are less shots coming in."