Fabianski has been the Gunners' Cup keeper this season ahead of Wojciech Szczesny.
"You play football on your merit and your performance and he has turned up with top-level performances until now in every single game," Wenger said.
"When you are a professional you work until the last day of your contract. That is for me being professional.
"All the rest has nothing to do with professionalism."
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