Chelsea boss Jose Mourinho has insisted that he is not concerned by his side's start to the season, but concedes that they are not "unbeatable".

The Blues fell to their first defeat of the season against Everton when Steven Naismith's first-half strike was enough to seal Roberto Martinez's maiden win as Toffees boss.

Mourinho told reporters: "No, it is not 2004 all over again. Then we lost against Manchester City in October – our only defeat. But that is not the point. We are not unbeatable. This is a different team.

"I came here to work – I don't say peacefully because I am the first one that does not like to work peacefully – but to work with time, to develop the players and play the best they and we can.

"We have to be effective, be adult and not naive. That is what we have to work on. We have to transform the ­beautiful football we played into goals."

Chelsea are sixth in the Premier League table after taking seven points from their opening four games.