Before Knockout 16

Group stage is over. All 5 South American teams (100%), 6 European temas out of 13(46%), 2 North American teams out of 3(66%), 2 Asian teams out of 4(50%) and only 1 African team out of 6(16%) have been selected to knockout 16.

South American teams showed a great success in group stage than European teams. Even africa have produced many world class players, still as a team African teams are not in the level of European and South American teams. But you can keep South America and Europe head to head. In that case teams came from similar latitudes to South Africa have performed well. May be the reason is Climate. Even though South American players have the practice plating in Europe, European players do not have the practice to play in tropical countries. This also came up in Confederation cup 2009. Both Italy and Spain were unsuccessful in the competition. If this is the case those retaining 6 European teams also will not have a successful journey in knockouts.

Knockout fixtures are set like this.
So teams in left will never play with teams in right until the final. Teams in the same side may play each other on the way to final. Now remember South Korea went all the way to semi finals in 2002 world cup. So any thing is possible in knockout stage. Good defensive tactics and luck can take any smaller footballing nation to pass giants. But if we take the general scenario it'll go like this

Knockout 16

Uruguay v S.Korea -> Uruguay
USA v Ghana -> Ghana
Argentina v Mexico -> Argentina
Germany v England -> Germany/England (Totally Unpredictable)
Netherlands v Slovakia -> Netherlands
Brazil v Chile -> Brazil
Paraguay v Japan -> Paraguay
Spain v Portugal -> Spain

Quarter Finals

Uruguay v Ghana -> Uruguay
Argentina v Germany/England -> Germany/England
Netherlands v Brazil -> Brazil/Netherlands (Totally Unpredictable)
Paraguay vs Spain -> Spain

Semi Finals

Uruguay vs Brazil/Netherlands -> Brazil/Netherlands
Germany/England v Spain -> Spain

Final

Brazil/Netherlands v Spain
1) Brazil v Spain -> Brazil
2) Netherlands v Spain -> Spain

If everything goes in usual way Brazil or Spain will be the champions. But we all know it'll not be like that. There will be upsets. That's the beauty of football. That's why we watch it.