Guus Hiddink has admitted Chelsea could become embroiled in a relegation battle with defeats to Everton and Arsenal in the next two games.
The champions of last season are 14th after 21 games, 12 points off their stated target of fourth place and just six clear of Sunderland, who occupy the final relegation place.
The Blues' predicament prompted Jose Mourinho's departure last month and Hiddink's appointment.
Chelsea are unbeaten in six games since Mourinho left, when they were one point off the drop zone, but the midweek draw with West Brom did little to ease concerns.
"It's reality," Hiddink said. "We were down when we started. We were one point off the relegation line, but now we have a little room to breathe.
"We have two difficult games coming up - Everton, who have a very good away record - and Arsenal. If you don't gather points there, you don't know what the others do. The Premier League can surprise you.
"There is a 12-point difference to Tottenham in fourth.
"We like to look forward and to the top, 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 points to step up. That's why it was a pity that West Brom scored in the 86th minute, a win would've helped us a lot to move up."