Chelsea boss Carlo Ancelotti has revealed the Blues are low on confidence following a string of indifferent results. The Blues were firm favourites to claim the title after overcoming Arsenal 3-0 at Emirates Stadium last month.
However, they were not able to carry that momentum into December and have picked up just one victory from their past five games.
"I think we lost a little bit of confidence in our play," said the Chelsea tactician said.
"This is normal when you don't get results.
"But we must maintain concentration because in a season it can happen that you have to overcome a difficult period."
Manchester United and Arsenal made up more ground in the title race with wins on Sunday, after Chelsea had been held to a goalless draw by Birmingham on Boxing Day.
"I think other teams have a possibility to win this title," he admitted.
"We cannot say which teams now - it will be a long race until the end of the season.
"We did very well until the match against Arsenal and now we are a little bit down.
"But we gave signs against Birmingham that are good for the future.
"Our aim is to win the title and we are top of the list at the halfway point."
