When the USMNT take the field tonight for the semifinal, they will have one small advantage over Argentina. The U.S. last played on Thursday, while Argentina played Saturday. That gives the U.S. two days extra rest over Argentina, who have a mere three days to recover from Venezuela. Now, Argentina was well rested for their quarterfinal game and were able to win without completely exhausting themselves. However, those two days really are a significant advantage
Soccer is an intense sport with a limited number of substitutions and continuous stop-start play. On average, players run around seven miles in 90 minutes. Some players can run almost 10 miles during a game. After a match, it takes time for players to recuperate, with most leagues allocating a week and teams rotating for midweek games.
If Argentina are taking the United States seriously, which I am absolutely certain they are, they will be limiting how much they rotate. That is especially true considering Angel Di Maria is injured and Nicolás Gaitán is suspended. With some grit and a good game plan, the U.S. might be able to take advantage of the more tired Argentinians and grab a surprise win.