Before you begin to talk about which players will start in midfield for the U.S. against Costa Rica next week, you have to consider how the midfield will line up.

Ever since Jurgen Klinsmann's first game at the helm of the national team in August of 2011, the U.S. coach has favored stationing one defensive midfielder just above the back four, a stay-at-home type who shields the line by moving laterally and winning tackles, putting out fires before they start.

A look at Yanks lineups over the last 19 months reveals only a handful of times when Klinsmann didn't play without a pure "No. 6." For the most part, those instances all had one thing in common: They were must-win games for the U.S.

Next Friday's World Cup qualifier against Costa Rica at Dick's Sporting Goods Park in suburban Denver certainly falls into that category. If there's any question that the formula for clinching a berth at the world's biggest sporting event hinges on winning home games, look no further than CONCACAF's last three World Cup cycles. According to numbers compiled by U.S. Soccer, the squads that successfully made it to the main event averaged a minimum of 15.75 points during the 10-game final "Hexagonal" round of qualifying. In other words, win out at home and you only need one solitary point from five away matches to get to the World Cup.