The USA was defeated by Nigeria in Football [Soccer] and was elimiated from the Olympics. Even though the USA was able to resist, it was unable to withstand the onslaught of the Nigerian Team. In fact, the Nigerians won 2 to 0 against the USA. It appears that the USA underestimated the Nigerian Team or that there was exhaustion. It should also be remembered that Nigeria is Football [Soccer] country in Africa while the USA is still in the adoloescent stage in football [soccer]. Regardless, it was expected that the USA would advance to the next stage in the Olympic Football [Soccer] Competition. 

REFERENCE:

US Soccer.com: «Down to 10 Men After Three Minutes, Valiant U.S. Effort Falls Short as 2-1 Loss to Nigeria Knocks Them Out of 2008 Olympics»

http://www.ussoccer.com/articles/viewArticle.jsp_8945664.html