Giroud opened the scoring in a 6-1 rout against Coventry City in the Capital One Cup before missing a second-half penalty.
Wenger believes that the French international can only improve after breaking his duck in his seventh Arsenal match.
He told the club's official website: "It is positive of course. He is a good finisher, Olivier. That goal will help him.
"I now expect him to take that confidence into the Champions League."
Arsenal continue a run of three consecutive home games in all competitions with a London derby against Chelsea on Saturday, September 29.