Chelsea manager Frank Lampard was left "concerned" after his side were thrashed 3-0 by Sheffield United.
David McGoldrick ended the long wait for his first ever Premier League goal, netting a brace either side of an Oli McBurnie header.
Chelsea were very poor, getting repeatedly caught out at the back and offering little in attack but Lampard highlighted the fact that his players were not being vocal enough on the field as a major source of disappointment.
Speaking to Sky Sports after the game, Lampard said: "They were better than us, physically, in the mind and with the ball. So you lose the game. They were stronger than us.
"You feel and hear every noise and all I could hear was Sheffield United voices. They are a good team. If you come here and perform below par this is what will happen.
"We matched them shape wise. We were too slow and weren't getting our wingers into the game. We tried to get control, which we did but weren't threatening.
"At 2-0 down you make it difficult for yourselves. Disappointing. Mistakes. You analyse all season and review and move forward. We need to put that to bed quickly and fight for the top four. I learned a lot and I won't forget that.
"I am not concerned about top four today. All I do is sit and watch the games and consider what we want to do. But today I am concerned with how we performed.
"We will see where we are when we approach Norwich. But we can't approach Norwich or Manchester United or Wolves like we did today."
Chelsea currently sit third in the Premier League but, if Leicester and United win their respective games in hand against Bournemouth and Southampton then they will drop out of the Champions League places which would be a major blow.