There's a saying : The offence makes the show, but the defence brings victories.
In the game with China , US players had many 1 on 1 situations with their opponents. Here they are unbeatable. (at 1 on 1), but the situation will change when they will meet the solid defences of Greece and Spain (hope that Spain's game vs. China was an accident)
I am not so sure that US will march so easy to the final victory...