Szczesny has been impressed with the Welsh club, and says Arsène Wenger's side will have to be at their best to beat them on Saturday.
"I think they're a quality team, so it will be a very tough game and a very important game," he told Arsenal Player.
"They have changed their style a little bit, they don't keep possession for ages, they are a little bit more direct. But they still try to play very good football and as a football fan, I appreciate that: I like watching them.
"Going forward they score a lot of goals, but hopefully they won't on Saturday. I have been watching them and they have impressed me. But we are very confident, we should be winning these kind of games at home."