Having allowed Juve to get back into the Group E clash before half-time, Chelsea looked set to eke out a 2-1 win before Mikel needlessly gave the ball away 10 minutes from time.
He then failed to prevent Claudio Marchisio playing Fabio Quagliarella into space for the equaliser, with David Luiz also all at sea.
"If I want to make up an excuse, I can," Mikel said.
"But, for me, I gave the ball away. I put my hands up, we move on.
"I'm sorry about the mistake, but there are no excuses."