Holloway was concerned by the reaction of his side after Nathan Redmond fired the visitors ahead against the run of play in the 24th minute.
Damien Delaney headed into his own net six minutes later, and Palace were found wanting in the final third as their 18-match unbeaten home run came to an abrupt end.
The result put a huge dent in Palace's hopes of automatic promotion, and Hollway said: "No one was expecting that, I certainly wasn't.
"Unfortunately I have got to deal with it right now. I think we started the game brightly, got behind them a couple of times.
"We didn't pick out the right ball, didn't get people on the end of it and then their goal seemed to affect everybody out there, which is completely unusual.
"Then they got a second one from a set piece and I was expecting a response like we did away at Watford.
"I can't remember my team missing as many balls flying across the box or making as many wrong decisions as they did out there and they've gone and scored four. That is the last thing we need but we've got to get on with it.
"We have to bounce back and deal with things better. It is simple as that."