The stupid thing is you could have seen this was going to happen. Tierney and willian kept being pegged back into that corner a number of times before the goal actually happened. If you're going to blame Xhaka then you have to blame those two plus Leno for constantly losing the ball in that position and playing the ball in the penalty box. When I was in a football team I was always told never to play the ball around in the box or across goal. Defending 101 clearly went out the window for the whole defence. Leno is just lucky Xhaka became the fall guy when he was stupid enough to make the worst pass possible. He should have just cleared it out if no one was free.