It wasn't Clark. He was covering Mata. The defenders next to him moved too far to the right, leaving the penalty area exposed, and Rooney totally free as he came from deep. He should have had a midfielder on him, or a defense that would stand tighter inside the penalty area. If anything this was the second bad game in a row by Vlaar. Poor Clark trying to cover up his mistakes and then gets the blame anyway.
Maybe it is a management issue, maybe it is experience, maybe it is a discipline issue where the players can't follow instructions . Either way, it will get better. I think this team has a lot of talent, and this second season syndrome and new to this league syndrome will eventually go next season and we will see the real Villa challenging for top 6.
Clark never should of left Rooney like that. Mata was in between Westwood and Delph when the ball came in. It was terrible defending from Clark.