Jose Mourinho has ordered his Chelsea players to recapture their winning mentality when they face Schalke in the Champions League at Stamford Bridge on Wednesday.
Mourinho admitted he was shocked by the side's attitude in their 2-0 Premier League defeat at Newcastle United last weekend and has demanded a positive response.
The loss came after six straight wins and Mourinho accused his players of forgetting "why" they were winning.
"I had lots of time to watch the game, to reflect on the game, and I don't change my opinion," Mourinho said on Tuesday.
"I don't want my team to be reactive. This is not the philosophy we are working on, and I'm not happy with the way we faced that match.
"My teams can lose matches. My teams always lost some matches. Never unbeatable. Chelsea is the same," added the Portuguese, now in his second spell in charge of the London club.
"But there are losses and 'losses', because you're not the team with the determination or ambition we want us to have.
"That was the case. That was the reason I was disappointed."
Mourinho said he made 11 selection mistakes at the weekend, but that does not mean he will make sweeping changes against Schalke.
"It's not about changing 11, and I don't want you to see the changes I make as somebody paying for the defeat against Newcastle.
"That's not the case. It's simply that I read the game and I read it once, twice, three times, and you try to analyse the way people perform.
"After that, you have to go in the direction of the Schalke game, see the characteristics of the opponents, try to make the changes and not to punish people."
Fernando Torres, who scored twice in Chelsea's 3-0 Group E win over Schalke in Germany last month, will miss Wednesday's match as he has suffered a muscular injury and needs a scan to determine the extent of the damage.
His absence means either Samuel Eto'o or Demba Ba will lead the attack.
"Samuel and Demba. They want to play," Mourinho said
"They are waiting for opportunities to play. So when they have that chance, and they know they are going to have it in this game and the next game against West Brom.
"They know it's in their hands, the job to play up front. I think it has to be a good motivation for them.
"Hopefully they can express on the pitch the way they work during the week."
Chelsea centre-back Gary Cahill said Mourinho was right to criticise the players after their weekend performance.
"The manager's going to be frustrated when a result is disappointing. Likewise the players," said Cahill.
"We were looking to maintain the momentum and got a poor result. But as players you want to get straight back out there and put things right.
"This is an opportunity to do that. We have to move on, look to respond, and bounce back from the weekend."