The Gunners manager is confident that there is still more to come from the Welshman after the latest in a series of goals helped his side to down Swansea City
The Welshman's outstanding start to the season continued as he scored one and set up another in the Gunners' 2-1 triumph at Swansea City, taking his tally to eight goals in nine club appearances this season and moving his side two points clear at the top of the Premier League.
When quizzed about the 22-year-old's performance, a delighted Wenger told Sky Sports: "Much like the team, he had a difficult start but he became stronger. He had an outstanding second half and scored again. What can you say?
"There's still a lot of improvement to come from him."
Wenger also hailed the efforts of German youngster Serge Gnabry, who made the most of the absences of wingers Theo Walcott and Alex Oxlade-Chamberlain to produce a terrific performance, including the opening goal.
"He is 18 years old," the Frenchman added. "Early quality on the pitch is what he is showing. We are giving him confidence and he had another good game."
The Gunners boss felt that his side were distinctly average in the first half but was pleased with their response, explaining: "The first half was quite difficult. I felt we were a little bit slow in our combinations and Swansea were a little sharper than us.
"[In] the second half we were much stronger. We took advantage of the chances we created. We have substance in the team and you could see that in the second half. We came out with purpose and won the game. That was important.
"Our spirit has been tested after the first home game [losing to Aston Villa] and, the way we responded, it is very positive."