It's not just Wilshere's fault. Syn was right about Monreal. As a defender you need to be aware of the players around you and the runs they are making. Nacho doesn't have that awareness and even before they scored their first goal he was ball-watching when the ball was on the other flank, leaving their RW free on the right. I was watching him, he didn't even turn once and a good ball in behind him would have left the RW in a great position behind our defence. That's exactly what happened for their second goal.
If you watch Sagna you will always see him looking around to see where their attackers are. That's what I like about him - he's a defender first and foremost and knows what he's doing, unlike any of our other three fullbacks.