Estadio Azteca is the gold standard of the CONCACAF region.
Azteca seats 105,000 fans who aren't known for being quiet. And this massive structure is not built in a classic bowl shape like the Rose Bowl in Pasadena, another 100,000-seat stadium in the CONCACAF region. Instead, it was built with two tiers of stands, so all of your favorite Mexican supporters are right on top of you. And it resides in Mexico City, which is 7,349 feet above sea level and had an average high temperature of 77 degrees during the 2011 calendar year.
All these factors help give Mexico a nearly insurmountable home field advantage, and they wisely schedule their most important World Cup Qualifiers at this venue.
But Azteca has lost some of its currency in recent weeks. For an August 15 friendly against bitter rival United States, Mexico inexplicably scheduled the match for Azteca, instead of at another venue somewhere else around the country. Azteca was loud, but was not filled to capacity due to the decreased significance of the match. Consequently, the Americans played in a less intimidating environment and were able to play much better. In fact, the 1-0 win was the first victory by the Americans in Mexico in the 75-year history of the cross-border series.
So what was originally a meaningless game turned into a valuable experience for Mexico's fiercest rival. Team USA now knows they can win in Azteca, and will be more comfortable in the stadium, even with a full house.
The rest of CONCACAF is surely taking notice.