Chelsea star striker Didier Drogba has admitted he sometimes drifts in and out of games and loses concentration.

"Yes, it happens to me many times, it happens to every one of us," he tells November's Chelsea Magazine.

"It's funny because there are some times in the game where you don't touch the ball for a while and then you realise that the crowd is there, or they're not reacting, or you notice something specific going on and focus on it.

"After that you have to come back into the game quick because this is how you lose your attention and sometimes you can mis-control when the ball comes to you suddenly, or miss an opportunity."

Drogba, who is currently sidelined with a knee injury, says it is essential to be mentally strong as a lone striker.

"When you play alone in attack you need a special preparation, a special warm-up so that mentally you are ready, otherwise you cannot play to the best of your ability.

"I think about what I am going to do to escape my marker, what I am going to do to score goals.

"I actually think about the way I am going to score my goal - I close my eyes and try to imagine it and sometimes it doesn't happen.

"But most of the time when you get it in your head that you are going to score a certain kind of goal, it happens.

"It's funny but you create something in your head, a desire to score, an attitude and everything can go like this in the game.

"It's different with two up front, a completely different approach - you have to think with your partner, have the same ideas as him and not think only for yourself in the game.

"Now my game is much more about coming deep, touching the ball and then moving into space.

"I need to be on the limit of offside when the pass comes.

"I've scored a lot of goals where it looks close to offside but the assistant referee can't say because I'm always right on the limit."

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