Chelsea head coach Guus Hiddink warned his side to heed a wake-up call after the Blues nervously held out for a 4-3 victory at home to Bolton Wanderers.
The home side were four goals ahead on the hour mark at Stamford Bridge thanks to goals from Michael Ballack, Frank Lampard and a Didier Drogba double, but were forced to hang on at the end after allowing the Trotters to hit back to 4-3.
Hiddink fumed: "It was a wake-up call for us and we talked to the boys straight after the game. If you play at the top, you cannot afford to do it twice.
"We must not let it happen again. It is normal that the players react to the situation.
"It was a typical English game. We were leading 4-0 with 20 minutes to go and waiting for a fifth. All of a sudden we got very sloppy and too relaxed and didn't win any duels defensively.
"I am not just talking about the defence, but also the midfield and front players. We conceded three goals in nine minutes I think - that should not be possible against a team that is near the top of the table.
"We did not perform well. There were a sequence of errors that we made.
"I don't think the substitutions were the cause. We were just too relaxed in the last 20 minutes."