Wenger opted to rest first-choice shot-stopper Wojciech Szczesny, who he claimed was “mentally” fatigued, in favour of Fabianski for the Gunners’ 2-0 win at Bayern Munich.
The 27-year-old produced a largely impressive display at the Allianz Arena and has given the Gunners boss a selection headache ahead of Arsenal’s trip to Swansea on Saturday.
“He played with authority. We know his talent and I’m very happy with his performance,” Wenger told Arsenal Player.
“He has changed a lot, there has been a complete mental transformation in Lukasz’s attitude. He is more vocal, has more authority and mentally he absorbs the pressure of the game much better.
“He has a huge talent, which we know all about. Sometimes to go out of the game for a while helps people to mature and think about their own game. If they really want to become a better player, they think, ‘How can I become better’.
“I think it is a combination of both [working with him and his own maturity] but I would give him 90 per cent of the credit. He works on all the aspects of his game.”