José Mourinho rarely changes his lineup for Chelsea, which has caused some players to be frustrated by their lack of playing time.

"I'm very club, club, team, team, club, group [orientated]," the Portuguese said. "I think everybody has to be ready to sacrifice for the team, to give everything for the team, to think about the team, not to be selfish. This is the way I want a team to be.

"I think it is right when you say that players are unhappy or players are frustrated, that they need to be patient. I don't have a secret to keep players happy.

"But the reality is that, to be professional and work at a high level, you don't need to be happy. All of them are professionals.

"The team is more important than themselves, and the club [is].

"Even the ones not playing like [Mark] Schwarzer, who hasn't played a second, but if he has to play tomorrow he would be ready. Why? Because he is very professional and he trains very well.

"We don't have a secret to keep them happy because we don't keep them happy.

"We may have a secret to make them work every day at a high level."