While finding the net has not been a problem for his side in recent weeks, Wenger acknowledges that they need to tighten up at the back.
"Finding the balance is an issue. Look at the number of shots on target we've had in the last five games - you'll be surprised," he told the club's official website.
"Last year we had 17 clean sheets with the same defenders but we have not started to do that yet. Our defensive efficiency is not there and we cannot survive at the top level by always conceding two goals."
Arsenal are back in Champions League action on Wednesday when they travel to Belgium to face Anderlecht.