Chelsea midfielder Nemanja Matic has admitted that he is at a loss to explain why his side have struggled so much this season.

The Premier League champions currently sit just a point above the relegation zone, having slumped to their ninth league defeat of the season at the hands of Leicester City on Monday night.

Jose Mourinho's side have taken just four points from the last 21 available, and Matic acknowledged that a vast improvement is needed if they are to make anything of the campaign.

"I cannot explain why consistency has been so difficult to achieve," he told the club's official website.

"We are sad because of the defeat [to Leicester], but we have to keep going, to try to win some games and to recover from this situation which is not easy for us. We have to try to be better than we were."

Chelsea have made their worst start to a season since 1978, when they ended up being relegated.