Arsène Wenger has praised Thomas Vermaelen\'s \"nose in the box\" - but says his attack-minded side must be careful not to get caught on the break. Arsenal were undone by two counter-attacks in Monday night\'s 2-1 defeat to Wigan at Emirates Stadium, leaving Wenger unhappy with his team\'s defending. And he says that when the likes of Vermaelen go forward, his team-mates must cover for him. \"Thomas Vermaelen has been absolutely vital for us. He has a nose in the box to find a goal where it is needed and I must say he is a good finisher,\" he told the Official Matchday Programme. \"He is the only one, along with Robin, who gets on the end of crosses with headers. When you see him head the ball you have hope that he will score because he really goes for it. \"I like him to go forward on set-pieces but I don\'t like that we are caught on the break. \"The first job of a centre back is to not concede goals. On the night [against Wigan] I think that we were not focused enough as a unit at the back to do our first job, which was to defend well.\"