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Brasilia: In big events the form generally works out - save the odd, glorious exception such as Australian teenager Nick Kyrgios, whose defeat of Rafa Nadal at Wimbledon has turned the tennis world upside down.

The World Cup has been a different matter. In all eight round of 16 matches - the first games of the knockout stage - the team that progressed as winners of their group have triumphed.

There have been some close shaves as five of the eight ties went to extra time and two of them - the Brazil v Chile encounter and the Costa Rica v Greece match - were only decided by the narrowest of margins, penalties. 

Colombia: the most impressive side so far.

Colombia: the most impressive side so far. Photo: AFP

But the form book held sound as all eight group winners - Brazil, Netherlands, Colombia, Costa Rica, France, Germany, Argentina and Belgium - all went through to the quarter-finals.

So that's that's three South American nations - two of whom, co-incidentally, play each other in the first of the last eight ties - one Central American representative and four countries from Europe in the final eight.

Interestingly, however, the final eight in the World Cup bear only a partial relationship to the top eight in the FIFA rankings released a week before the tournament kicked off.

Brazil were a coat of paint from being knocked out by Chile.

Brazil were a coat of paint from being knocked out by Chile. Photo: AP

Germany (2), Brazil (3), Argentina (5) and Colombia (8), can be said to have justified their seedings. But Belgium (11), Netherlands (15), France (17) and Costa Rica (28) have achieved more than some might have expected.

But the gap is closing. The history books will show that the top teams progressed, which might make it look as though this has been an easy to predict World Cup.

Nothing could be further from the truth.

Bryan Ruiz: starred in Costa Rica's World Cup run.

Bryan Ruiz: starred in Costa Rica's World Cup run. Photo: AFP

Brazil came within a coat of paint of being eliminated when Chile hit the bar in the last moments of extra time in their nail biting game in Belo Horizonte, triumphing only after a nerve-wracking penalty shootout. 

Germany had to survive a fierce onslaught from the outsiders of Algeria to make it through in extra time.

Argentina looked sluggish and unconvincing (Lionel Messi aside) before they finally disposed of a stubborn Switzerland with barely two minutes of extra time left on the clock, while Belgium also had to sweat through extra time against a determined USA. The Europeans created far more chances and were the better team, but they could take nothing for granted until the final whistle went in a 2-1 victory.

Argentina have been a one-man team so far.

Argentina have been a one-man team so far. Photo: Reuters

The only group winner who might be cut some slack is Costa Rica. They lost key defender Oscar Duarte to a red card half way through second half of their tie against Greece and held out until stoppage time, when Greece grabbed an equaliser to take the game into extra time. Few would have given the 10 man Ticos much chance of holding out for another half hour, but they did and held their nerve to win the shootout.

The Netherlands must count as the luckiest of the round of 16 winners. Trailing Mexico 1-0 with barely three minutes left, Louis Van Gaal's team got level with a Wesley Sneijder thunderbolt and then, in the last minute, got a penalty when Arjen Robben theatrically flung himself to ground following a rash Rafa Marquez challenge.

Klaas-Jan Huntelaar coolly despatched the spot-kick and the Oranje were through in the most dramatic of circumstances. Robben admitted subsequently that he gone to ground too easily during the match - cold comfort for the distraught Mexicans.

France face Germany in the quarter-finals.

France face Germany in the quarter-finals. Photo: Getty Images

So what looms now?

Brazil was taken to the end of its tether by the quick, skilful and tenacious Chileans and were lucky to go through.

Their next assignment is even harder, against the hugely-impressive Colombians. Jose Pekerman's team was the only one to come through their round of 16 assignment with relative ease, seeing off a Luis Suarez-less Uruguay by a comfortable 2-0 scoreline in the Maracana.

Romelu Lukaku came off the bench to score the winner for Belgium against the US.

Romelu Lukaku came off the bench to score the winner for Belgium against the US. Photo: Reuters

Plenty of people will regard the Colombians as favourites when this game kicks off in Fortaleza on Friday (Saturday morning AEST).

The France v Germany quarter-final rekindles memories of their epic semi-final clash in 1982, when the Germans came back from 3-1 down in extra time to draw level and beat Les Bleus on penalties. It was also a game remembered for one of the worst fouls in World Cup history, when German goalkeeper Harald ''Toni'' Schumacher poleaxed Frenchman Patrick Battiston in a cynical and brutal challenge, ensuring the France defender had to be stretchered off and taken to hospital.

Costa Rica have never progressed this far before and are the genuine surprise team of the tournament. They have seen off plenty of big names already and will have taken plenty of encouragement from the fact that Mexico, a team they finished ahead of in the qualifiers, gave the Dutch so much trouble.

Germany's midfielder Mesut Ozil (left) scores his team's second goal against Algeria.

Germany's midfielder Mesut Ozil (left) scores his team's second goal against Algeria. Photo: AFP

Argentina and Belgium face off in the other quarter-final and this promises to be a fascinating clash. The Diego Maradona led Argentina beat the Red Devils in the semi-final in 1986, and Messi might have to put in a similar one man effort to get the unimpressive Albicelestes over the line against the Belgians, who should have put the USA away earlier than they did in their first knock out game.

The winners of the Brazil v Colombia and France v Germany match meet in the semi-final in Belo Horizonte next Tuesday, while the two to emerge from the Costa Rica v Netherlands and Argentina v Belgium clashes meet a day later in Sao Paolo. 

With no stand out team everything remains up in the air. Colombia have looked the most impressive in their four wins out of four, but their acid test comes when they play the hosts. If they can win that, then the will take some beating for the rest of the tournament.