The biggest soccer tournament in South American history has delivered fans with so much excitement thus far. This week the eight remaining teams will all play each other head to head in four must watch elimination knockout games where the four winners will advance to the semifinals.

Chile, Argentina and Brazil won their respective groups with Bolivia, Paraguay, Uruguay, Peru and Colombia qualifying as well. The championship game won't be played until July 4, but everyone is already wondering; who will win it all?

Argentina remains the favorite by most soccer experts, and rightfully so. Argentina has arguably the best player in the world in Lionel Messi, they're the top ranked team in this tournament, and they haven't lost a single game. Argentina ranks No. 3 in the world behind only Germany and (somehow) Belgium.

There really aren 't many excuses for Argentina. Brazil and Uruguay (two top 10 teams) are both without their most skilled scorers in Neymar and Luis Suarez because of suspensions handed down by FIFA. The biggest threats to Argentina ending their 1993 title drought could be Chile and Colombia.

Brazil, as expected, won group C, which was by far the most difficult group of this competition. Thiago Silva connected on a one timer from a corner kick right in front of the net. If Brazil lost that game, they would have been eliminated. Silva's goal was one of the most crucial goals for Brazil in recent memory.

Brazil has been very successful at the Copa America winning this event eight times, the third most ever. But of course, we can't overlook the obvious downside going forward. Neymar will not be on the field. The Brazilian Football Federation is appealing the suspension, but it isn't expected to get overturned. Brazil will face Paraguay in their opening knockout game with a chance for revenge. Paraguay eliminated Brazil in the 2011 Copa America.

One of the other favorites to win this event is Colombia. Colombia has a very skilled middle field led by James Rodriguez, but they won't have an easy game beginning in the knockout round. Colombia, because they placed third in Group C, must face Argentina on Friday. Colombia and Argentina are the two highest ranked national teams in this tournament.

We also can't forget about the winner of Group A, and of course the host nation. Chilean fans are very satisfied with where their team is heading into the Copa America playoff. Chile won their group ahead of Bolivia, Mexico and Ecuador. Although Chile has never won this event before, they have one of the best goalies in the world in Claudio Bravo and the leading scorer in Arturo Vidal.

Chile has scored the most goals so far with 10, and they have the highest goal differential, plus seven.

Chile, Brazil, Colombia and Argentina are the "big four" favorites remaining, but four other squads still want a piece of the championship action. Uruguay barely squeaked in, but they can never be counted out. Uruguay is always in contention to win this tournament having won it more than any other country, 15 times. Bolivia is ranked No. 89 in the world, the highest of any team competing, but don't tell them. Bolivia and Peru will square off on Thursday.

Conventional wisdom and odds would tell us that Brazil, Argentina, Chile and Peru will win this week setting up an all-time great second round, but we know anything can happen.

Who do you think will win the Copa America? Feel free to vote in our fan poll below.

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