Mata's agent Fahid Ben Khalfallah blasted Stajcic last week for freezing out the former Manchester United and Chelsea star.
Stajcic is quoted by Reuters: "His agent doesn't control the team.
"I don't need to talk to agents when their players aren't playing. To be honest, I think his comments were out of proportion. They were wrong and they were wrong for several reasons.
"I've only talked to him (Fahid Ben Khalfallah) two or three times in my life. He has talked to me about how as many of his players as he has in Australia have been abused by coaches.
"They have been swindled or abused, emotionally, physically, whatever, and he has never opened his mouth to protect his player. And his player, in this case, was sitting on the bench and it was so disrespectful. I think his comments were flawed."
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