It's a good thing for the United States that Mexico isn't playing with a real attacking midfielder. The guy they're playing behind Javier Hernandez at the moment, Angel Reyna, usually plays as a winger and certainly doesn't have any experience as an attacking midfielder at this high of a level. Mexico's normal attacking midfielder, Giovani dos Santos, is injured and in London. It's a good thing for the USMNT.
Whether because he knows Reyna isn't great in his current role or because he's insane, Jurgen Klinsmann has his team set up in a way that a top quality attacking midfielder could exploit easily. Jose Torres isn't defending by design and Kyle Beckerman is pressing by design, leaving the hot-headed Jermaine Jones and attack-minded Danny Williams to cover the midfield. There's a lot of space around and behind them, but no one's exploiting it.
Elias Hernandez is sitting on the bench licking his chops. If he enters for Reyna in the second half, Klinsmann's going to have to adjust.