Charlton boss Lee Bowyer vowed there will be no repeat of their “unacceptable” performance in a 4-2 defeat at Burton.
Having arrived at the Pirelli Stadium with the best defensive record in the division, the Addicks conceded four times to a team who started the night bottom of League One.
“What do you put the performance down to? Maybe complacency, sloppiness,” Bowyer fumed.
“Maybe because we were unbeaten in eight, we feel we can just turn up to games and win. It’s not that simple, football isn’t like that.
“I’ve reminded a few of them in there, that is not acceptable – and that will never be acceptable, not playing for me.”
An unusually sloppy Charlton defence gifted Albion a 2-0 lead as errors from Chris Gunter and keeper Ben Amos allowed Lucas Akins and Joe Powell to fire home.
Paul Smyth reduced the arrears almost immediately but Albion pressed on in the second half to score twice more through Sam Hughes and Charles Vernam with their first Brewers goals, sandwiching a superb finish from substitute Chuks Aneke.
Bowyer was left to rue the chances missed by another of his bench players.
“It was just crazy,” he said. “Conor Washington came on with 20 minutes left and he could have had a hat-trick. He should have had a hat-trick. The game should have been 7-7.
“That is just not like us at all and the worst thing is it was the more senior players who were doing it, who have been in the game forever.
“We’ve got to put it to bed and just get ready for the weekend. We’ve got to dust ourselves down. We will revisit this game but they won’t make those mistakes again.”
Jake Buxton praised his Burton side for their work rate and application after the stunning win.
“I am absolutely delighted with the result, but equally with the performance,” said Buxton.
“To a man everyone stuck to the game plan and when you come off a pitch you should (have given) everything, and the players did that tonight and that is what I am proud of.
“I was on my knees after the game on Saturday. Some harsh words were spoken about some players taking a step back and not forwards.
“In the situation we are in we need to make sure we are all on the same page and doing the right thing.
“Tonight you could see how much it meant to the lads, the result, the performance and how much they had to dig in and work hard together.
“That is why they get the result, a togetherness and the graft and mentality to work hard and win a game of football.”