Alex Neil branded Preston's performance "unacceptable" after they lost 3-1 to Sky Bet League One side Doncaster in the FA Cup third round.
Two goals in the final quarter saw Rovers cause an upset against their Championship opponents at Deepdale and book a place in the fourth round for the first time in nine seasons.
Donny went in front thanks to John Marquis' fifth-minute header during an open first half.
They were pegged back by an Andrew Hughes header as Preston started the second period strongly.
But Tom Anderson scrambled the ball home with 18 minutes to go to put the visitors in control and sealed the win when Mallik Wilks slotted home in the 87th minute.
Preston boss Neil said: "I think during my time here, off the top of my head there have been five or six games where I have felt it has been unacceptable in terms of performance, and that was one of them.
"What I will say is that's pretty much the same team who have churned out so many games recently, but I don't want to make excuses, I will take full responsibility for today's performance and result.
"I don't think we've played poorly in the last three games up until this one. I thought Andrew Hughes was our best player on the pitch.
"We need to get back to trying to play as well as we can and picking up wins because we haven't been getting the results.
"Everyone knows that goals change games. The second goal was a disappointing one to concede, and the third goal is a comedy of errors really and that finishes the game."
Doncaster boss Grant McCann, however, could not contain his delight after the impressive victory.
"I thought we were outstanding today. I'm particularly proud of the response after we conceded," he said.
"We stayed mentally strong and re-established control. From that goal we were again the better team and the team who looked most likely to win.
"I have to praise the defence. They allowed our front six to go out and express themselves.
"Preston showed us respect by naming almost the same team they had in the league last time out.
"I told the players before the game to go and show that they can compete at this level and I think they've done that.
"It is a great feeling to be in the fourth round, it has been a long time since the club got so far. We are all excited to see who we will get drawn against."