Mauricio Pochettino admitted Chelsea lacked hunger and intensity in their disappointing 2-2 draw with 10-man Burnley on Saturday.
Pochettino's team was booed off yet again as furious Chelsea fans let loose after their latest collapse at Stamford Bridge.
With 12 minutes remaining, Cole Palmer blasted into the bottom corner following Raheem Sterling's pass, putting Chelsea on track for a 2-1 victory.
Burnley's Josh Cullen leveled on the volley early in the second half, after Palmer given Chelsea the lead from the penalty spot.
Burnley's Lorenz Assignon had been dismissed in the penalty incident for his foul on Mykhailo Mudryk, with Clarets boss Vincent Kompany was also sent from the touchline for remonstrating.
But Chelsea still couldn't get the job done as Dara O'Shea headed past Djordje Petrovic's weak attempted save in the 81st minute.
Pochettino was seething with his players' lack of drive against a team sitting second bottom of the Premier League.
"Today we didn't show the capacity, the energy, the hunger. Not the minimum to compete in the Premier League. In defensive phases, we concede too much," Pochettino said.
"That is why I'm so upset and disappointed. It's more here (in the heart) and here (in the head) than in your legs. It's about being strong like a group, strong like a team.
"We are too slow evolving in this area. That was the key today. But when we didn't have the ball, we don't have the same energy.
"Today, sorry, I am not happy with the performance when we don't have the ball. It's difficult to accept not to win. It was a must-win game."
Chelsea's five-game unbeaten league run is the longest in over 18 months, but fans showed little support for Pochettino and his players at the conclusion.
They lost further ground in what appears to be a forlorn effort to qualify for Europe, putting even more pressure on Pochettino in his problematic first season in command.
Chelsea is in mid-table and lost the League Cup final against an inexperienced Liverpool side.