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.”