Filipe Luis has claimed that Chelsea must not allow their performance levels to drop in the second half of the season.

Chelsea hold a three-point advantage at the top of the table at the halfway stage, but Luis believes that the tests will only become tougher for Jose Mourinho's side.

"The second half of the competition is the more difficult one," the Brazilian defender told reporters.

"We have to keep the level really high because we know it is going to be really difficult, but we are happy because it is not easy being top of the league for the whole competition until now.

"We feel that if we keep playing in the second half like we are playing now we can be there at the top of the league at the end."

Chelsea are back in action against Tottenham Hotspur on New Year's Day.