Peterborough United boss Luke Williams says their performance against Port Vale was as disappointing as he has "ever seen" from a team he has managed.
Posh lost 3-1 at home on Thursday and have now taken only two points from their past five games, dragging them back into the relegation picture.
Ethon Archer scored twice with free-kicks for the visitors, but Williams said both were the result of "needless fouls".
Peterborough are 16th with four matches to play and despite having 51 points and a game in hand on the sides below them, are only four clear of the drop zone.
"We seemed to have a lot of territory and were able to get to their box fairly comfortably but there was no conviction at all and we had to rely on a set-piece to score a goal, we can't score a goal from open play," Williams told BBC Radio Cambridgeshire.
"It sounds crazy, but I miss the team. What I've seen recently, that's not the team I saw really fighting for everything and prepared to leave everything out on the pitch and come off exhausted – and winning.
"I miss that group. For one reason or another, players are not able to find their top levels, their top energy, their quality (at the moment).
"They were a brilliant group and I'd love to see them back to their best."
Three of Peterborough's remaining games will be at the Weston Homes Stadium, the first against Burton Albion on Sunday.
"I've tried many things, of course, and tried to remind them of some of the (good) performances they've put in… and see if we can reignite that energy," Williams said.
He will assess striker Jimmy-Jay Morgan, who missed the match against Vale, before Sunday's game.
"It's not an injury, but he was in a lot of discomfort and pain, that should settle down very quickly," Williams added.
