The Chilean referee did it really well. During the match there weren't many controversial actions, but he managed to always be in control. He only booked twice, and that was enough.
I think there is no doubt about the penalty he conceded. Milito pushed Eddie Johnson, clearly, and the USA could score the first goal. Nothing to say against that decision.
Just as we have been critical with linesmen that have flagged wrongly, we want to be fair here and say that assistant Rodrigo Gonzalez was perfect in not flagging for offside when Riquelme gave an excellent ball to Tevez, who scored the 4th for Argentina. It was a difficult ball to judge, but Gonzalez was perfect.
This was not an outstanding performance by the "Albiceleste". But it was enough for them with the 2nd half to show the great level of some of their players. Riquelme, Messi, Crespo and Tevez made the difference.