Chelsea manager Thomas Tuchel says he cannot explain the recent “fragile” home form which has seen the club lose three successive games at Stamford Bridge for the first time since 1993.
The Blues also suffered a 4-1 defeat by Brentford earlier in April and lost 3-1 to Real Madrid in the Champions League.
“It’s unusual and I don’t know what it is,” Tuchel said, before West Ham’s league visit on Sunday (14:00 BST).
“If it was just the one thing, we would switch dressing rooms or take another hotel. But that would maybe be more superstition than anything else,” the Chelsea boss added.
“I have no solution but it’s also not the level that we want to produce in home games. It’s a bit fragile at the moment.”
FA Cup finalists Chelsea are third in the Premier League, five points ahead of Tottenham and Arsenal in the race to secure a top-four place and Champions League qualification.
Tuchel believes the condition of the pitch at Stamford Bridge has not helped his side of late – and referenced Andreas Christensen’s back-pass, which allowed Arsenal to score the opening goal in midweek, as an example.
“The first goal was from Andreas but it was because of a funny bounce,” Tuchel said.
“It was awkward to calculate the speed and bounce of the ball. I know everybody’s working hard in every department to provide the best level.
“We are struggling a bit with the timing of the renewal [of the grass] this season. This leads to a bit of the problem.
“The pitch wasn’t where it should and could be at the beginning of the season.”