Chelsea manager Maurizio Sarri says his side have reached their mental “limit” after their top-four hopes were dented by Everton’s second-half resurgence.
The visitors dominated possession in the first half with Eden Hazard striking the post and Pedro wasting a chance from close range.
But their profligacy was punished four minutes after the break as Richarlison headed in following a corner for his 13th goal of the season.
And the visitors’ woes increased on 71 minutes when Richarlison was brought down in the area by Marcos Alonso, with Gylfi Sigurdsson scoring the rebound from his own penalty.
As a result, Chelsea failed to capitalise on their game in hand, and still sit sixth in the Premier League table, a point behind Manchester United, who they would have leapfrogged had they won. Victory would also have taken them level on points with fourth-placed Arsenal.
“We played probably the best 45 minutes of the season and then suddenly at the beginning of the second half we stopped playing; I don’t know why,” said Sarri.
“It is impossible that the situation is a physical problem because if it is, you can go down gradually, not in one second.
“It is very difficult for me to explain the change. Probably it is a mental block.”
When asked how worried he was that Chelsea’s mental situation has not been solved, Sarri said: “At the moment, this is our limit.
“If we are able to play like in the first half with consistency, then we are in another position in the table.”
For Everton, a first home win since 13 January was a much-needed response following last weekend’s defeat at Newcastle in which they lost 3-2 having led by two goals.
In that game, Jordan Pickford was an erratic presence in goal, but this time where there was no dip from Marco Silva’s side and the England goalkeeper made a remarkable save to stop Gonzalo Higuain’s deflected shot shortly after the hosts went ahead.