Chelsea keeper Cech impressed by Mikel improvement
Cech was already at the club when Mikel joined from Lyn Oslo in 2006 and is in no doubt he has developed into a key member of the squad.
He said: "Everybody has their opinion but ever since John Obi joined us he's been a player who has played a lot of games - all the important games.
"He's never missing. If he's available for selection, he plays. He's very useful and part of our success in the last few years. He's a massive player for us and we're happy to have him in the team, no matter what other people think."