Mexico's opening match Thursday did nothing to allay the fears of those who believed El Tri was heading into the Olympics in a slump.

In its 0-0 draw with South Korea, Mexico failed to establish any offensive rhythm, was often forced to play too far back defensively and has left manager Luis Fernando Tena with some difficult decisions leading up to the next group match on Sunday against Gabon.

What will Tena choose to do now that benched Giovani Dos Santos' substitution helped spark the little offense El Tri did show on Thursday? Would Tena dare to start Jorge Enriquez over Hector Herrera since Enriquez was much more impressive during his time on the field? What will Tena make of Oribe Peralta's mostly listless performance, especially when Raul Jimenez came on as a sub and played well in just five minutes of action?

For the first time since Copa America, Tena's decisions in such a quick tournament could very well determine Mexico's fate in these Games.

Clearly, Mexico's back line problems leading up to the games dictated how it played. Mexico often seemed all too content to have its entire team play in the defensive half. Mexico's defenders all did well to maintain their marks, but the problems of the recent past dissuaded the back line from taking any chances. Defenders rarely passed the ball up the field to start an offensive run. When given the opportunity, they cleared the ball toward the sideline to avoid any gaffes.

Such a strategy disrupted any offensive surge. The only offensive plays started from the back line came on long, overhead passes that often missed their mark.