Chelsea star Kurt Zouma admits they must improve mentally

Kurt Zouma has suggested it is taking Chelsea time to adjust to being the defending Premier League champions.

Jose Mourinho's side are the one the others are trying to dethrone and on Saturday lost 2-1 to Crystal Palace - the team against whom they secured the title in May.

Chelsea, after a second loss in Mourinho's 100th home league game, have four points from their opening four matches and are eight points behind rivals Manchester City.

"We have to improve everything," Zouma told Chelsea TV.

"Mentally we have to improve. The season after we are champions, it's really difficult to prepare ourselves.

"To improve is more difficult, but we have to improve ourselves and keep going, keep working."