The manner of the 2-1 loss against the Bluebirds led to booing at the final whistle, PNE having surrendered a half-time lead and allowed their visitors to boss large parts of the second half.
Then it is back to Deepdale on Saturday lunchtime to face free-scoring Fulham in front of the Sky cameras.
Head coach McAvoy was rueful at the way the Cardiff game panned out.
Sean Maguire’s goal inside 90 seconds was the start of a decent display in the first half.
But things went badly wrong after half-time, Cardiff bringing James Collins off the bench really unsettling PNE.
The Welsh side scored with two headers from set-pieces, Collins getting the winner.
McAvoy said: “They made one change at half-time, Collins came on and for some reason that made it a bit more difficult for us.
“We weren’t brave enough at times to get on the ball when we were 1-0 up.
“Sometimes you need to be able to do that, it’s not just a case of clearing your lines and hoping that something happens from there.
“There were a couple of times when players got into good areas and then gave the ball away which was unlike them – that was disappointing.
“Once we were chasing the game you hoped we would have enough quality to unlock them but unfortunately we didn’t have that.”
McAvoy said Cardiff’s winner was the first goal PNE had conceded from a corner this season.
The equaliser had come from a free-kick delivered into the middle.
Said McAvoy: “That’s the first goal we have conceded from a corner.
“Collins gets above Andrew Hughes and Patrick Bauer, while Daniel Iversen is caught in an area you don’t want your goalkeeper to be in.
“In the main we have defended set pieces really well but on this occasion we didn’t.
“For the first goal we have got done at the back stick where Mark McGuinness gets the better of Sepp van den Berg two or three yards out.”
PNE had one chance at 1-1 to restore their lead, Ryan Ledson having a shot saved.
But they created nothing after falling behind.
McAvoy said: “We had Emil Riis up there, we put Scotty Sinclair on as well, we brought DJ on.
“In hindsight we could have put DJ on earlier, maybe we could have changed it earlier when we were under the cosh.
“That is something I have to look at myself.”