Mauricio Pochettino admitted Chelsea lacked hunger and energy during their dismal 2-2 draw with 10-man Burnley on Saturday.
Pochettino's side were booed off yet again as frustrated Chelsea fans let rip following their latest stumble at Stamford Bridge.
When Cole Palmer drilled into the bottom corner from Raheem Sterling's flick with 12 minutes left, Chelsea were on course to escape with a narrow victory.
Josh Cullen had equalised for Burnley on the volley early in the second half after Palmer gave 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 they have enjoyed in almost 18 months, but there was little positive cheer shown by fans at the end towards Pochettino and his players.
They lost further ground in what looks an increasingly doomed bid to qualify for Europe, increasing the pressure on Pochettino in his troubled first season in charge.
Chelsea are languishing in mid-table and were beaten by an inexperienced Liverpool side in the League Cup final.
They could salvage the season by winning the FA Cup, with a semi-final against holders Manchester City looming in April.
To do that, Pochettino conceded they must conquer the psychological root of their lacklustre displays.
"The players need to realise that competing is different to playing football. We can be there and play, but we need to increase our level," he said.
"It's not about blaming the players. Maybe we (the coaching staff) need to be tougher with them.
"We need to be more ruthless, find better communication, be more competitive.
"We are missing something. That's why we are where we are. When we don't have the ball we need to increase our capacity to recover it."
