Mata insisted Chelsea's players had not been cowed by the jeers and abuse that have dogged Benitez's short reign.
"I'm not deaf, so we were aware," he said of the fan backlash.
"The supporters are free to do whatever they want. My job, our job, is to play well and to win. That's all I care about."
The 24-year-old added: "I always try to be focused on what I'm doing, nothing else.
"If we want to win, if we want to lift trophies this season, we have to be all together, fight as a unit in the team."