Former Chelsea midfielder Michael Ballack has praised the work that manager Antonio Conte has done at the club this season.
The Blues lead the Premier League standings by eight points after 22 games, and Ballack believes it comes down to the way the players have adapted to Conte, and the fact that they have no European football distracting them.
"The surprise was, last year, that they were so bad," he said, according to Goal.
"That they are top of the league now is not a great surprise because they have the advantage of not playing European football.
"The team looks really fit, the team have adapted really well to the new coach, who has adapted really well to English football, and the team is playing to their strengths, making very few mistakes, not conceding many goals.
"That's the key if you want to win a title – to be solid.
"At the beginning they conceded a few goals and then they changed tactics and went to 3-4-3. That was important as well, the players feel comfortable.
"If you want to perform at 100 per cent you need trust at the club, with the people you work with and Conte is doing that."