Arsenal goalkeeper Wojciech Szczesny says the Gunners know they must avoid the same set-piece problems faced on Saturday when they play Borussia Dortmund in the Champions League.
After showing flashes of brilliance to take the lead, a Martín Demichelis header prevented the Gunners from taking all three points with the 24-year-old admitting that defending from set-pieces is still a concern.
"We do realise that set pieces have been a weakness for us recently," Szczesny said on Monday.
"We've conceded [a couple] of goals already and it's very early in the season.
"We did very well last season on set pieces and we're a bit disappointed.
"We've been working on it in training so hopefully we'll put that right on Tuesday."
The Gunners will be without defender Mathieu Debuchy who is expected to be on the sidelines for months after suffering a serious ankle injury.
"It's very disappointing to lose such an important player," added the goalkeeper.
"He's had a very strong start to the season, he's very experienced and he's a very solid right back so we're disappointed to lose him but hopefully he'll be back as soon as possible.
"I have no difficulty playing with any of the defenders.
"We try to communicate in training so I don't think that's too much of an issue."
