Watch Shakhtar Donetsk vs Fulham Live Streaming
Watch Shakhtar Donetsk vs Fulham Live StreamingVilla were undone by two set piece goals when their first meeting ended in a 2-2 draw at Selhurst Park.
But they have the meanest defence in the Premier League - conceding just 21 goals in the top flight so far - and O'Neill added: "A very big plus for us this season has been the inclusion of such players as Stephen Warnock, James Collins and Richard Dunne.
"Dunne is kind of quiet but he is natural leader as he leads by example. For anyone who comes into the side I would think that the confidence the other players are exuding should rub off on them."
Victory for Villa against Palace would take O'Neill closer to unchartered territory in the FA Cup.
The furthest he has ever gone is the quarter-finals and victory against Palace would set-up a place in the last eight against either local rivals West Brom or Reading.
He said: "The quarter-final is the furthest I've been in the FA Cup. I've done it three times as a player at Nottingham Forest, Norwich and at Notts County.
