Larrionda did an acceptable job, but we are used to see him refereeing on the highest level. Today it was not his best performance: there were some little mistakes and some not-so-big-but-not-so-little ones. From the beginning, he tended to control the game trying not to be repressive. He preferred not to use cards, even when some fouls deserved them. He showed 4 yellow, and two of them were shown during the last 2 minutes of the match. Paraguayan defenders were rude enough to warrant more than that.
Of course Larrionda didn´t loose his style. Always right on top of the ball, always making the players feel that he's the boss. The game didn't have any controversial moments (a penalty, a red card, something like that). Argentina was the team that wanted to win it. And they won because of Messi and Mascherano, who scored a magnificent goal.
Larrionda is a strong contender to referee the Final, or at least one of the Semi-Finals. But this will depend on what happens with Uruguay in the quarterfinal match against Venezuela. If Uruguay qualifies for the semis, Larrionda will have to say "Goodbye" to this Copa América.