I didn't think it made contact at first, but the replay showed he took a fair whack in the back of the head. I'd imagine you wouldn't get straight up from that if it was you. Ashley Young took a hell of a beating in that game, any time he tried to break he got absolutely flattened.
There was no whack to the back of the head, if anywhere the keeper got him in the lower back. As for Young, he was the main offender when it came to diving.
I can't see either us us budging to be fair so i'll just say that although I didn't think Villa deserved their win today, good luck to them against their opponents in the next round.