I just think Belgium has the quality AND experience to beat the US.
Belgian players have more experience due to where they play, also physically they might edge out because of this.
This has proven a key factor in all Knock out games so far, where the smaller nation usually peters out at the end of the game and the experience and physical training of the big team come through.
Mexico, Algeria, Nigeria, all played well but in the end they couldn't hold out anymore.
I heard the US has a physically well prepared team so I'm curious if they can stand the full 90 min. Klinsmann is experienced enough to let them pace themselves.