Frank Lampard was to see his young team improve on their concentration and focus in order to overcome Valencia on Wednesday.
The Blues were beaten on home soil by the Spanish club in their first Champions League meeting this season.
And in order to exact revenge at the Mestalla, Lampard knows his players have their minds on the job.
Speaking of their first clash, Lampard said: "I felt we were the better team.
"My major feeling after the first game is the lesson that will always be there, whether you're 18 or 32, is that if you sleep for one moment at Champions League level you can lose a game.
"We will have to take every bit of concentration and focus into this game. The rules always remain the same, particularly when you're travelling in the Champions League, particularly when you come to a stadium like this which is a fantastic stadium to play football, but can be a very difficult one when you're the opposition coming here."
On Valencia's quality, Lampard added: "I expect a very organised team, a team with quality in attacking areas, the two strikers and the wide players they have.
"My feeling having played at this stadium, it's not just this team, it's the support and the atmosphere when they come together and they're playing well, it's a difficult game for everybody. I expect a difficult match.
"Champions League games can be a battle in midfield, they can be tight, they can be difficult, but you have to be clinical in both boxes, particularly when there is so much at stake and the match is tight."
