The Gunners have failed to hit their peak form in the Premier League as they have taken just 11 points from their opening eight matches of the campaign.
Although Wenger feels that that their struggles may have been due to fatigue from players returning from the World Cup, he is adamant that they have to improve quickly.
Wenger told reporters: "I think 95% is there. It is normal that after a World Cup, and we have new players, you see the main thing is there – the attitude, the quality.
"But the water boils at 100 degrees and not at 99, and we have to add that degree. It is frustrating, but we have to play better. That is how we have to think. We dominate our games.
"It is just when we have a weaker moment we pay for it. That is why I think we have to produce more effort defensively as a team."
Arsenal face Sunderland in their Premier League clash at the Stadium of Light later today.