Relegation is a possibility for Chelsea, says the Premier League champions' interim boss Guus Hiddink.
The Blues are 14th in the top flight, six points off the bottom three, and their next two league games are at home to Everton and away to Arsenal.
"It's reality," said Hiddink, who took over from Jose Mourinho in December. "We have two difficult games coming up.
"If you don't gather points there, you don't know what the others do. The Premier League can surprise you."
Chelsea were one point above the relegation zone when Mourinho departed the club.
|Chelsea's next five Premier League fixtures|
|Saturday 16 January||Everton (h)|
|Sunday 24 January||Arsenal (a)|
|Wednesday 3 February||Watford (a)|
|Sunday 7 February||Man Utd (h)|
|Saturday 13 February||Newcastle (h)|
The Stamford Bridge side then beat Sunderland, after which Hiddink took over as manager.
"There are 12 points difference to fourth place, which is Tottenham," added the Dutchman.
"We all like to look forward and to the top of the table, but also don't be unrealistic - you're six points off the line of relegation. That's also a fact.
"We have to work hard and be very concentrated and gather our points to step up."