He said: "We have already won at Stamford Bridge this season. We ended their long unbeaten home record and that is a massive boost to our confidence.
"We can do it, if we work together and we score in the first half. If we do not do that it becomes increasingly more difficult, mentally.
"If we score a second goal then they will be under real pressure. But we know we must be almost perfect.
"And we know that with Steven and Fernando (Torres) together on the pitch we do have a good chance.
"People have written us off. Maybe we have nothing to lose, which means we can be positive, relax and hopefully then not make mistakes.
"We want to score an early goal, that is very important. But we will need to be calm and not lose our concentration. Bolton scored three, so it can be done, but Chelsea had already scored four, so you can see how hard it is to beat them at Stamford Bridge.