Friday night's display - especially in a first half that saw Radamel Falcao plunder a hat-trick - bordered on the clueless.
Cech said: "Sometimes, it's nice to get a slap in the face.
"It's important in football to learn from the lesson and to avoid it in the future and this will be the key."
Midfielder John Obi Mikel added: "It is a kick in the backside. We have to take it and we have to keep our heads up and make sure it doesn't happen again."