Former Chelsea midfielder Michael Ballack lauded manager Antonio Conte for guiding Chelsea back to the Premier League summit.
Chelsea faltered dramatically in their title defence last season as Jose Mourinho lost his job and the Londoners finished 10th.
But with Conte at the helm, Chelsea are top of the table, eight points clear of Arsenal after 22 matches.
And Ballack praised the work of the former Juventus boss at Stamford Bridge.
"The surprise was, last year, that they were so bad," he said. "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.
"That's a lot of factors coming together and that's why Chelsea are dominating the league so far."
Ballack, who won the Premier League with Chelsea in 2009-10, also praised Conte for the way he has handled striker Diego Costa.
Costa was dropped for Chelsea's clash against Leicester City following a reported fallout over a back injury amid interest from the Chinese Super League, before he was recalled and scored in the 2-0 win over Hull City on Sunday.
"First I have to congratulate Costa for getting an offer like that! I never got one.
"But this is normal. You love what you do but it's still a job and you are limited in time earning money and you think about it if someone makes you a crazy offer.
"I think it is an emotional aspect, and also with toughness that Conte took him out of the squad, which was an understandable situation.
"But also the answer's good from Costa. They are two really high-class professionals dealing with each other. One is the coach, the other is the player and overall there is the club.
"He has a contract and if he understands that this is the right club and he should do his job, then it should work."