The Pole gaffed in his comeback game against Southampton on Saturday.
"Wojciech is No 1 unless I change my mind," declared the Frenchman. "That is clear. That's why he came back in goal.
"You cannot change a goalkeeper every time he makes a simple mistake, because then you have three bad keepers. The confidence is needed.
"It's a special position where confidence is needed. Maybe he put himself a little bit under pressure because he knows [Vito] Mannone played well at Stoke and at Liverpool. I think he played better in the second half."