London - Arsenal manager Arsene Wenger has said only a vastly improved defensive effort will propel the Gunners back towards the summit of English football.
The Gunners have lost just once in the Premier League so far this season, to leaders Chelsea.
However, several draws have proved costly and Wenger's side will kick off 11 points behind London rivals Chelsea when they face Sunderland on Saturday.
They will, though, head to the north-east on the back of a win after two goals in the final two minutes in Belgium saw them to an unlikely 2-1 victory over Anderlecht in the Champions League on Wednesday.
That result, however, could not mask the kind of defensive problems on show in last weekend's 2-2 draw with Hull.
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Wenger stressed Friday that the issue of Arsenal's defending extended beyond criticism of a back four who have been hampered by injuries, with centre-half Laurent Koscielny set to be sidelined for at least a month with an Achilles problem.
"Until now we have been relatively consistent in our attitude and in our performances, but not efficient enough, neither defensively nor offensively," said Wenger.
"If you look since the start of the season we have only lost two games, to Dortmund and Chelsea, but we didn't make enough points with our performances," the veteran French manager added.
"It is improving by getting everybody to put a bit more effort in to the defensive work, and that starts not only at the back, but up front and in midfield by increasing the level of defensive activity through the team.
"We had to reshuffle the defence and (the players) getting used to playing together helps as well.
"Last year we had 17 clean sheets and at the moment we have only had one after eight (Premier League) games, so that is something which we are not on the same level defensively.
"We train very hard and the spirit is right, the attitude is here. I believe more it is linked with confidence at the moment, but I cannot fault the attitude.
"It (the win at Anderlecht) will help to improve confidence and I am sure that if we focus on our performance, the rest will come naturally."
Sunderland were thrashed 8-0 by Southampton last time out and Wenger expects a backlash from the Black Cats, especially in front of their own north-east home crowd.
"When you go to Sunderland, you know to always expect commitment and fight for 90 minutes and we have to prepare ourselves for that," he said.
"The result from last week will certainly have dropped their confidence and increased their resolve to defend well, and then you can get very few openings, so it is up to us to just focus on our own performance."