Jose Mourinho believes his Chelsea side ``forgot'' the reasons for their six-match winning streak in losing at Newcastle at the weekend.
The Blues will this week bid to bounce back from the surprise defeat at St James' Park, which followed six wins in October, including against Wednesday's Champions League Group E opponents Schalke.
``When you win a lot, you cannot forget why you win,'' Mourinho said.
``You cannot think that you win just because you have a nice shirt or you are on a good run or you are in a lucky moment.
``When you think that, you are in trouble. You never can forget why you are winning matches and maybe we forgot.
``I hope now they don't forget why they won a lot of matches and why they lost against Newcastle. If they have that clear in their minds we are fine.''
Chelsea play at Stamford Bridge in the Champions League for the first time since Swiss side Basle inflicted the Blues' first home loss in the group stage of the tournament in 29 matches and nearly 10 years.
Since then they have won 4-0 at Steaua Bucharest and 3-0 at Schalke, with two goals from Fernando Torres, who is sidelined and faces a scan on Wednesday to determine the extent of his leg injury suffered in training.
Torres will miss Saturday's match with West Brom while left-back Ryan Bertrand, who withdrew from training on Tuesday, is also absent for the Schalke contest.
Torres' unavailability gives Samuel Eto'o, a Champions League winner with Barcelona and Mourinho's Inter Milan, and Demba Ba an opportunity.
``They work to play, they want to play, they are waiting for opportunities to play,'' Mourinho added.
``Hopefully they can express on the pitch the way they work during the week.''
Chelsea overtook Schalke at the top of Group E by winning in Gelsenkirchen two weeks' ago, hitting the Germans on the counter attack.
Schalke have won just once in England in European competition in six attempts, beating Arsenal in October 2012 at the Emirates Stadium.
Coach Jens Keller is eager for his side to make an impression in London.
``We haven't won yet against the big boys and we know we've got a really big game ahead of us here,'' Keller said.
``We're not here just to be visitors. We want to take something from the game.''
Kevin-Prince Boateng, meanwhile, hopes to be in his more customary midfield role on Wednesday.
Two weeks ago at the Veltins Arena, the former Tottenham player struggled to get to grips when deployed as a 'false nine', a deep-lying striker.
``It's not my favourite position and I haven't played a lot of games in that position,'' Boateng said.
``Hopefully tomorrow he (Keller) is going to put me in another position.''