Shkodran Mustafi says Arsenal must be wary of Eintracht Frankfurt's attacking players.
The Gunners host Frankfurt at the Emirates on Thursday night.
"You noticed from the beginning in Frankfurt that they're a team with identity," Mustafi said.
"You could see what they were trying to do and how they were trying to play. The players knew what to do, how they were moving and it's always difficult to play against very organised teams like that and they have the individual quality to hurt you as well.
"You can tell their idea of the game and how they want to play. Nothing is random, they're very coordinated. Even if you know how they play, you can't always anticipate it as a defender. If you anticipate their attacking moves, you may open up different spaces for them to capitalise on.
"It's a team with attacking strengths so you have to be focused for 90 minutes. They don't hog possession without gaining any space. They're very organised on the ball and want to get it back as soon as possible. It's hard to play against teams like these. It's not easy.
"We had to be fully focused for 90 minutes and play when we had our chances, when we had our moments of the game to finish them off. We did that well. In this game they had a red card which made it easier for us towards the end, but I think the team did very well when we played in Frankfurt."