London:
There's no crisis talk at Stamford Bridge but events in the last fortnight have prompted Chelsea's first bout of soul-searching since the pre-season arrival of manager Carlo Ancelotti.
The Blues saw out November with an emphatic 3-0 victory at Arsenal that led to Ancelotti's side being hailed as Premier League champions-elect in some quarters.
But the mood has darkened since that game with a league defeat at Manchester City following a League Cup loss to Blackburn before this week's scrambled home Champions League draw with APOEL Nicosia that the manager described as the worst performance since he took charge.
Suddenly the poise that accompanied Chelsea's controlled start to the season looks a little less assured and there will be an added edge to their home meeting with Everton this weekend.
Manchester United's victory at West Ham last weekend meant the champions capitalised on Chelsea's loss at City, cutting the London club's advantage at the head of the Premier League to just two points.
Another slip against Everton and the two leading clubs could be back on level terms, with the balance of power shifting towards Old Trafford.
No wonder, then, that Chelsea midfielder Joe Cole saw the meeting with the Merseysiders as a key match.
"We need to bounce back at the weekend and get back to winning ways," the England international said. "Hopefully, we can do that on Saturday.
"The next five Premier League games are very important. The Christmas period is always vital. We want to still be sitting on top of the league at the start of January. If we do that we'll be very happy.
"Any team can beat you in the Premier League and it's very difficult to win games. There are no excuses. We're sitting on top of the league now and need to be sitting there on January 1."
Chelsea will be without influential midfielder Michael Essien after the Ghana star tore his right hamstring against Nicosia.
Essien will be out for up to four weeks, after which he will be leaving for international duty at the African Cup of Nations.
That tournament looms large for Chelsea, who won't want to concede ground in the title race when they are set to be without Essien, Didier Drogba, Salomon Kalou and John Obi Mikel early in the New Year.
Everton visit west London on the back of last weekend's dramatic draw against Tottenham, when they recovered from a two-goal deficit.
Their season was in danger of entering a serious decline but the spirit demonstrated by David Moyes's men squad against Spurs gave hope that the Toffees were about to get themselves out of a sticky situation.
Everton could soon be bolstered by the arrival of the Los Angeles Galaxy's United States international midfielder Landon Donovan on loan, a welcome addition given the injury problems at Goodison Park.
Joseph Yobo is likely to miss the rest of December with a hamstring injury but at least manager Moyes can call on John Heitinga after the Dutchman missed the 2-2 draw with Tottenham through suspension.
Even though Republic of Ireland Under-21 international Seamus Coleman impressed as a substitute against Spurs, the defender is not expecting a starting spot at Stamford Bridge.
"I'm not going to look too far ahead of myself. I want to play, everyone wants to play, but I'm not going to be unrealistic," he said.
"It (the Spurs game) is only one game and one game is not going to make me a player, so I need to push on."