Sean Dyche warned that every shirt was up for grabs after the Clarets fell to a third straight defeat, away at Sheffield United.
The Clarets were down and out by half time at Bramall Lane, as they trailed to a John Lundstram brace and John Fleck’s decisive third just before the break.
And Dyche pulled no punches after insisting his players were “miles off” the performance levels needed to pick up points in the Premier League.
The Burnley boss said: “We’ve been down this road before and we know how tough it can be from last season, so this needs to be a bad day at the office and that’s it.
“It needs to be parked, but it won’t be parked easily because there were a number of things today.
“I mentioned to the players yesterday and how tight it was for decisions as to who plays. Well that throws it all back into the mix!
“I could have taken any of the back four off at half time, but every shirt is now up for grabs after a first half like that.”
Dyche, who made one change at half time, introducing Charlie Taylor at left back for Erik Pieters, added: “I spoke to them at the break about the journey we’ve been on from last season to this season, and the mentality that comes with that.
“We’ve shown that many times, but today we came up against a side that showed us what we do; the hunger and desire and the edge that you have to play with.
“We looked subservient; the body language, being dismissive with the ball and making poor decisions.
“We’ve been down that road before, but not for a long time and today was like being back at the start of last season.”
United bossed the opening 45 minutes and led when Lundstram slotted home a left wing cross in the 17th minute.
The Liverpudlian doubled the lead with a similar goal in the 43rd minute, before Fleck capitalised on defensive hesitancy to score the third two minutes later.
Dyche added: “It was nothing to do with tactics. We were miles off where we’ve been this season and they were deservedly in front.
“We’ve been punished recently, but today was about punishing ourselves.
“We weren’t at the races in the first half and that’s a concern because we looked like we were back at the beginning of last season.
“In and out of possession we were poor. We didn’t have that underlying edge that you need and at times in the first half we were knocking it forward with no need.
“For all the stories, we don’t ask them to knock it forward all the time. There’s a time and place to do that and be effective, but people were just passing the buck.
“I told them all that at half time in a slightly more aggressive manner than I am now, and at least there was a reaction.
“But they were miles better and deserved the victory. The thing is, Sheffield United are now being talked about as having a brilliant start, but if we’d won today that would have been us.
“That’s how fine the balance is. It’s so important to get on the right side and we didn’t do that today.”