I don't deny it will be a tough game (they all are in this division, to be fair), but looking at Preston's results, they've drawn games against Boro, Barnsley & Millwall - all of which we beat, and they've lost to Derby - again, another team we have already beaten this season. However, they did manage to hammer Cardiff, and they've held Leeds to a draw - so their form shows they're difficult to beat and can raise their game against the better teams in this league.
If we can get anywhere near our performance levels v Villa, we should still win.