Frank Lampard has called on Chelsea's new recruits to "wake up" and adjust to the demands of the Premier League following back-to-back losses.
The Blues temporarily moved top of the table with a 3-1 win over Leeds United on December 6 but have since lost away to Everton and Wolves.
Olivier Giroud had given Lampard's men the lead in Wednesday's (AEDT) clash at Molineux, only for Daniel Podence to equalise before Pedro Neto rifled in a 95th-minute winner.
Chelsea have spent over £200 million on new players this year and five of those - Edouard Mendy, Thiago Silva, Ben Chilwell, Kai Havertz and Timo Werner - started the Wolves defeat.
On the back of successive league losses for the first time in a year, Lampard urged his big-money captures to quickly learn from their latest setback.
"We need to reflect on the two games we have lost points in, which is disappointing, but also know this is a long season," he told the club's official website.
"We have to bounce back; the players have to bounce back.
"We're a young group, some players are new to this league, they need to wake up to what this is about right now, because games like the last two prove it."
Chelsea have a six-day gap between matches and could potentially be in the bottom half of the division by the time they face London rivals West Ham next Tuesday (AEDT).
Lampard is hopeful the short break will give his players an opportunity to rest up amid what is shaping up to be the tightest title race in years.
"They can have a little bit of a rest, hopefully not a happy rest because when you lose games you're not happy," he said.
"But physically the players need a bit of a break going into another really busy period.
"I don't like to look so much at the table when we are winning and on a long unbeaten run, and the same now.
"We have to worry about ourselves, irrespective of who is playing each other elsewhere. It's really tight. If we had won, we would have gone level on points at the top.
"If you lose, all of a sudden you feel like you might drop out of the top four, five, six, whatever it is.
"The longer game is for us to concentrate on, but we must think short term and the players must learn lessons because the games are coming thick and fast over Christmas.
"I know what we can do, and I know consistency is another matter.
"We had been on a long unbeaten run, great, but to really get to where we want to be it has to be longer than that, or if you have a blip you have to bounce back from that."