The Argentina midfielder has been impressive in recent weeks, helping Chelsea move into second-place on the Premier League table.
Obi Mikel said: "Sometimes you need that kick up your backside to get you to wake up. His performances weren't good at the start of the season and everyone was complaining.
"I think the manager took him out the firing line to protect him a little bit.
"Now, he's brought him back into the team. You can see his stats there. Absolutely fantastic. He's been absolutely fantastic since coming back into the team, and he is the captain right now. We need him to lead by example on the pitch."
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