By Jurgen Klinsmann's own determination, the World Cup has already been a success for the United States. With the U.S. drawing and losing their last two games it may not feel that way, but America has reached the knockout round, which was Klinsmann's stated goal prior to the tournament. But there are reasons to be optimistic heading into the showdown with Belgium.

For starters, the U.S. has played about as well as anyone could hope, putting in a complete team effort without relying too heavily on any single player. On the other bench, Belgium hasn't played up to the standard of their unofficial title as the world's dark horse. For any forward-looking and optimistic U.S. fan, this matchup always seemed the most likely -- Belgium's group was quite weak and the U.S. was never expected to top Germany and win the group -- but appeared far tougher before Belgium's unimpressive group stage. Of the group winners, the U.S. drew one of the more forgiving matchups.

The U.S. managed to advance without their best striker, Jozy Altidore, who injured his hamstring in the first half of the opening match. Altidore is reportedly fit for duty against Belgium, which is doubly good news considering Vincent Kompany, Belgium's world-class centerback, is 50-50. It's tough to say too much about this game without knowing if either or both of them will be on the field, but at least on paper, Belgium with Kompany isn't a great matchup for Jozy. They've been playing four centerbacks across the back, a formation that has yielded only one goal so far. Even with Jozy healthy enough to play, the U.S. may be better served by bringing him on as a late sub and attacking from the outside in, especially given defender Thomas Vermaelen will not be fit to start at fullback.

Attacking from the outside has been America's dominant strategy so far, with Klinsmann deploying Fabian Johnson on the right. This puts him on the same side as Eden Hazard, the most talented player on either roster and likely the key to the match. With Johnson bombing forward to help out in the attack, the American right has been routinely vulnerable to counters. Closing this window on Hazard without handcuffing Johnson's forward runs has to be a key focus for the Americans, particularly with Romelu Lukaku lurking as Belgium's target man. 

In many ways, Lukaku is the player Americans have been waiting for Jozy to become, a big, disruptive lone striker capable of manufacturing goals through sheer force of will. Although he hasn't played particularly well so far this tournament, he has the capacity to torment the inexperienced U.S. back line (we're at the point of the tournament where this can be said about every American potential opponent, especially if the U.S. advances and faces a likely matchup against Argentina), which raises some fresh concerns in itself. 

For the first two matches, Klinsmann played the expected centerback pairing of Matt Besler and Geoff Cameron. After his role in both Portugal goals, Klinsmann benched Cameron for Omar Gonzalez, the previous favorite who had fallen out of favor after several poor performances showcasing his frequency for defensive lapses. Somewhat surprisingly, Gonzalez played well against Germany, settling down after a shaky start and making several key clearances. So the question is, will Klinsmann go back to Cameron or stick with Omar?

In Cameron, Klinsmann gets a more experienced player with more caps under his belt. Plus, Cameron is more familiar with some of Belgium's key players, having played against Lukaku and Hazard in the English Premier League. On paper, Cameron seems like the easy choice, but Gonzalez's performance against Germany and the added physicality he can bring against Lukaku may have Klinsmann thinking otherwise.

The U.S. is certainly vulnerable at the back, but so are the Red Devils, particularly if Kompany can't go. However, America has arguably looked just as capable this tournament as Belgium, getting results against tougher competition. 

So much of this match depends on how each manager wants to play. Klinsmann proved he's perfectly willing to sit back, defend and counter against better sides in the 1-0 loss to Germany, but he's also demonstrated aggressiveness against Portugal. America's tactical flexibility has been a pleasant surprise but great performances from midfielders Jermaine Jones, Michael Bradley and Kyle Beckerman have provided the U.S. the kind of strategic flexibility they've rarely had in the past. Klinsmann can give Jones and Bradley heavy defensive duties or make Beckerman the lone defensive midfielder, or neither. It's been fascinating to see how Klinsmann deploys these three during the group stage and we're almost certainly in for a surprise or two personnel-wise against Belgium. 

For all the unpredictability of the group stage, the knockout rounds have seen the underdogs -- Mexico, Algeria, Nigeria and Chile -- put up strong performances in ultimately losing efforts thus far. America can certainly reverse this trend, but it will take one of their better World Cup performances. The U.S. is playing with house money now and that is when they're often at their best.