“Yes, I think it played a part last season (not being fit enough),” Mikel told .
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“One thing is for sure, the team is a lot fitter this season. A lot of players are going to be much, much fitter and that is only going to help the team.
“[Double sessions] That's the way he wants to train, that's his style, that's his way that he thinks we can win and that he thinks can get Chelsea back to where they belong. Obviously, quite a lot was made last year that a lot of the players were not fit, so the club decided to go for someone to make sure we are fit.
“The players have responded very well to him, we are going with whatever the manager wants to do in training, everyone is putting in their best and we have to keep going his way.”
Mikel is yet to make an appearance for Chelsea this season since he came back from the Rio 2016 Olympic Games when he won a bronze medal with the Nigeria U-23 team.