Simón looked concentrated and well located during the whole match. He was OK when booking, and had to sent-off Tevez because the Argentinian, reckless, hit a Paraguayan player with the sole of his right shoe. Simón was almost always in control. Argentinian players love talking and claiming things, so for Simón it was a good idea to show himself as the only boss.
Simón didn´t want to concede penalties. He could have done that because Demichelis was pushed at least twice inside the Paraguayan area (one of them was clear). Referees should whistle when a player wants to take the ball but then he´s restrained by an opponent. I think FIFA rules say that...
The last 4 games between Argentina and Paraguay played for WC qualifiers in Buenos Aires ended with the same score: 1-1.