It was truly an awful goal wasn't it? The trouble is when people discuss the concession of goals, they talk about systems rather than players when often it is individual mistakes which are to blame, not systems.
There were it looked to me three or four things wrong with the goal, two or three players to blame. Firstly, I cannot see why Riera doesn't head it. If you put a bloke on the front zone who isn't marking anybody, he has to head it. His job, is to ask the free kick taker a difficult question, he has to clear you before he gets it into the danger area. Arteta (I think it was) didn't, Riera should have headed it away. Nothing to do with systems that one, he just didn't attack it and clear the ball.
Now in behind him we have Hyppia and Skyrtel. I only saw the goal on the telly and haven't looked at it again (apart from on the replays obviously), but Skyrtel looks to me like he wanders off in behind Reina and into no mans land. He's not got a zone, and he ain't got Cahill either. Cahill ducks in front of Riena, and when Riera doersn't head it he scores the simplest of goals.
It's not the first time that Skyrtel has demonstrated his "standby" function, but it was the cruelest of moments for it to rear its head. I also can't understand given Everton's aerial danger (particularly from Cahill) why we didn't put Skrtel at the front where Riera was and tell hi to attack it.
We normally defend set-pieces extremely well in fairness, but that was not a good example. I don't though think any system in the World is going to compensate for one player not heading it, and another going to sleep. It was a truly awful goal, and I've no doubt it'll be studied at some length behind closed doors.