Chelsea manager Mauricio Pochettino accused his players of lacking the hunger needed to compete in the Premier League after his side were held to a 2-2 draw at home by 10-man Burnley on Saturday.
Despite Cole Palmer's brace, struggling Burnley came from behind twice and Dara O'Shea equalised late at Stamford Bridge.
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In the midst of a mediocre season, Chelsea remained in 11th place, with Burnley 19th in the table, four points from safety.
"Today we didn't show the capacity, the energy, the hunger that is the minimum to compete in the Premier League," Pochettino said in his post-match news conference. "In the defensive phase we conceded too much. That is why I am so upset and disappointed.
"It is more here [pointing to his heart] and more here [pointing to his head] than in your legs. It is more about being stronger as a group, stronger to be like a team. For different reasons we are so slow evolving in this area and that is the key today.
"It is not about finding excuses but the team played well, we had energy when we were going forward, but when we didn't have the ball we didn't show the same energy."
Chelsea were wasteful in the first half and had a goal ruled out after 20 minutes. The Blues took the lead from the spot when Palmer scored by chipping his penalty ball down the middle of the goal.
The decision after a VAR check to award the penalty to Chelsea for a foul on Mykhailo Mudryk in the box left Burnley coach Vincent Kompany fuming. Kompany was issued a red card for his vehement protest. Lorenz Assignon, who received a second yellow card for dragging down Mudryk, was also sent off.
Burnley pushed back and leveled against the run of the play when Josh Cullen volleyed home from 25 yards.
Palmer restored Chelsea's lead in the 78th from Raheem Sterling's flick but O'Shea snatched the equaliser with a header badly handled by goalkeeper Djordje Petrovic.
"We are very disappointed and frustrated in the way that in the second half we didn't deal with the situation," Pochettino added. "We are a team that when we play in possession and go forward are capable of creating many chances, but we didn't score with the chances we created. We need to increase our percentage of goals."
Palmer became the fifth player to reach 20 goal involvements in his first Premier League season with Chelsea. But it was little consolation for the England international.
"The changing room is really down," he told Sky Sports. "When they went down to 10 men, we were 1-0 up and just got too comfortable. Same story, we kill ourselves every week. It's got to improve from us as players.
"We had many chances and then that time we defended sloppy. It's very disappointing. On a personal level it's good to score two, but if you don't get the three points they count for nothing.
"I think it's our consistency all around the pitch, being alive and not switching off like we did today. It's poor, it can't happen. Especially when they go down to 10 men."
Chelsea will look to recover quickly when they welcome Manchester United to Stamford Bridge in the Premier League on Thursday.
"It is difficult to accept not winning the game, because I think it was a must-win game to have a chance to be in a different position," Pochettino said.
"We have to accept that, we need to recover from this situation. On Thursday we have another game here and we need to have the energy to be competitive. We need to clear our heads now."
Information from The Associated Press contributed to this report.