Chelsea manager Maurizio Sarri conceded "maybe I am not able to motivate these players" after the Blues suffered their heaviest league defeat for 23 years.
Wednesday's 4-0 loss at Bournemouth saw Chelsea slip to fifth in the table.
Sarri kept his players in the dressing room for more than 40 minutes after the game, later explaining he wanted to "talk to them alone, without anybody".
Sarri had previously said his team were "difficult to motivate" - after a 2-0 defeat by Arsenal earlier in January.
The Italian accepted responsibility for the defeat, saying it was "my fault", but after his side dominated possession in the first half Sarri said his players did not play as a team after the break and they "found it difficult to accept" going behind.
Two goals from Joshua King and one apiece from David Brooks and Charlie Daniels sent Chelsea to a second consecutive league defeat, while the Cherries climbed to 10th.
"At the end of the first half it was impossible to think the second would be a disaster and I want to understand why," said Sarri.
"Just like two months ago when we had to face difficulties, we lost our identity and played as 11 individuals."
Former Napoli boss Sarri replaced Antonio Conte as Chelsea boss in the summer. His side were unbeaten in their first 12 matches but have lost four of their past 12.
Sarri thought the "situation was apparently solved" when they beat Tottenham in the Carabao Cup semi-final last week.
But he said defeat at the Vitality Stadium means his players "need to change something in the mentality".
"You can concede but you need to play because the match was under control in the first half," he said.
"I am frustrated, of course, and it is a very strong setback because we knew this match was very important."
'Just keep it in the dressing room' - analysis
Ex-Aston Villa striker Dion Dublin on BBC Radio 5 live:
"I think Sarri calling the players out will have a detrimental effect. I don't think they like to hear their manager say those kinds of things. In public, it is not the done thing for me. If a manager wants to say anything, just keep it in the dressing room.
"Tell your players to their face you are not happy with this, you're hard to motivate. You'll accept that. But when you tell the public you're expecting a reaction, that is not going to help that togetherness they seem to be lacking at the moment."
Former Everton midfielder Leon Osman on BBC Radio 5 live:
"Chelsea seem a little bit soft through the core when their backs are against the wall and the going gets tough.
"The guy you expect to help - N'Golo Kante - isn't deployed where you would want him, in front of the back four to stop the opposition getting opportunities. He's at right-wing at times. It is a strange situation.
"Sure, he brings more offensively now but why would you want that when you have a player who does what he does? Jorginho played in there and Bournemouth scored four goals."
Former England striker Alan Shearer on Match of the Day:
"That was an embarrassing defeat and an embarrassing performance.
"When your back is against the wall you look to your team to find something, and he was forced to do that again for the second game in a row. It's his job to motivate the players.
"Bournemouth said they targeted Jorginho as a weakness and they stood on him. Sarri has got his man Gonzalo Higuain in now, and it has to improve."
- This was just the second time in Premier League history Chelsea have lost a game by a four-goal margin, after losing 5-1 to Liverpool in September 1996.
- The Blues have lost consecutive Premier League games for the first time since March 2018, when they were defeated by both Manchester clubs.
- Chelsea have won 47 points after 24 games this season - three fewer than at this stage in 2017-18 (50).
'Sarri can only blame himself' - how you reacted on social media
Chelsea's defeat sparked a debate on social media as some fans criticised Sarri's management style and his selection of midfielder Jorginho.
Marcus: Sarri can only blame himself and his poor management. You can't bring in Jorginho and make him instantly undroppable despite his inability to defend, assist or score.
Rich: Watching Chelsea under Sarri is reminiscent of Man Utd under Louis van Gaal. Side to side, backwards, with no cutting edge.
Shaun: Sarri is playing David Luiz as a centre-half, Kante as an attacking midfielder and has told Eden Hazard he can leave if he wants... starting to understand the fact he's won no trophies.
Some fans called for patience and used Liverpool manager Jurgen Klopp as an example of what Sarri could potentially achieve if given time.
Louis: Klopp finished eighth in his first season. As well as finally nurturing their youth, Chelsea also need to keep a manager for longer than two seasons. We need to build a team around the manager like Liverpool or Man City. That takes more than Jorginho and half a season.
Richard: Chelsea fans give him time, it's been six months. No-one gives anyone time anymore.
AP: Klopp took four seasons to build this team. Guardiola challenged in his second year after a massive overhaul and people are calling for Sarri's head after half a season. Fickle.
But some fans are already eyeing up a replacement for Sarri and former Chelsea midfielder Frank Lampard - currently in charge of Championship side Derby - is among the suggestions.
Stephen: Chelsea should sack Sarri in the morning and bring in Frank Lampard. What's the point in having so much possession but doing nothing with it? Football is all about goals.
Adrian: Give the job to Lampard. A young attack-minded manager with Chelsea running through his veins and let him build a dynasty.