Aitor Karanka believes Chelsea's lack of European commitments make them favourite to win the Premier League this season.
After an up-and-down start to Antonio Conte's Stamford Bridge reign, a switch to the Italian's favoured 3-4-3 system has reaped rich rewards in the form of five successive league victories without conceding a single goal.
A trip to Middlesbrough is next up for the Blues on Sunday, with Karanka hoping his side can replicate dogged displays which took a point apiece from games against Chelsea's title rivals Arsenal and Manchester City.
Both draws came after the Gunners and City had been in midweek Champions League action - a factor not lost on Jose Mourinho's former right-hand man.
"I have been impressed with them," Karanka said of Chelsea.
"Their manager has settled into the league really well, and within a few months he has his team second in the table and showing they are a really consistent team.
"They are scoring goals, and it is difficult to score against them.
"I think they are the favourites to win the league because they can take advantage of not playing midweek games in the Europa League or Champions League.
"In the future, I am sure they will get a benefit from not playing those games.
"They don't have midweek games and that is really important.
"If you look at our last game against Manchester City, I was asked in the press whether they might have been tired because they had played against Barcelona. We are in November, and those questions are being raised.
"If you look at the last four or five seasons with Chelsea, they were in the same position, but now it is different for them.
"We are only in November, but some teams are already having problems from a fitness point of view, so imagine what they will be like in February, March or April. They have a really good squad, a really good coach, and they also have that advantage."