Antonio Conte conceded Chelsea are out of the title race after their 1-0 defeat at West Ham.
Marko Arnautovic’s early goal condemned the Blues to a fourth defeat of the season and left them 11 points adrift of leaders Manchester City.
Tiemoue Bakayoko was poor in Chelsea’s midfield muddle, and boss Conte admitted: “This is the fourth defeat in 16 games. When you have these stats it’s impossible to think you are in the title race.
“If you want to stay in the race for the title in the first part of the season you can only lose once or twice.”
Chelsea were carved open far too easily with West Ham’s first attack in the sixth minute, when Arnautovic played a quick one-two with Manuel Lanzini.
The Austrian nipped in behind Andreas Christensen and, as Cesar Azpilicueta stood off, curled his shot around the defender and keeper Thibaut Courtois.
Chelsea had plenty of time to respond, yet it was a strangely subdued display from a side with six wins from their previous seven outings.
When their clearest chance arrived, six minutes from time, Alvaro Morata snatched at his shot and clipped the sidenetting.
“Today it was very difficult, our start was bad and it was difficult to come back,” added Conte.
“We created chances but didn’t take them and now we are talking about a defeat.
“Many of the players were tired. It’s normal. We started our pre-season with the same players, a lot of players are playing almost always.
“Today our ideas were not so clear. We made a lot of mistakes from the final pass. We can do better.”