ARGENTINA v BELGIUM: Unconvincing Argentina, eager Belgium

Argentina arrived in Brazil with Lionel Messi as their standard-bearer and with the declared aim of winning the World Cup, while Belgium's young side had long been billed as a likely dark horse.

When the two meet in the quarter-finals on Saturday in Brasilia, both will be facing their toughest challenge so far in the tournament, and they will need to shift up a gear if they want to play in Wednesday's semi-final in Sao Paulo.

"This is probably one of the most important matches in recent years for our country," Javier Mascherano told dpa this week.

Twice world champions Argentina have not played a World Cup semi-final since 1990, and they were eliminated in the quarter-finals in both 2006 and 2010.

Belgium have only played one semi-final in their history, in 1986, and they lost it to later world champions Argentina. The European side have not even qualified for the last two World Cups, but their team with Eden Hazard, Thibaut Courtois and Romelu Lukaku is making waves in Brazil.

Argentina and Belgium have had quite a similar World Cup record in Brazil so far. They won their three group-round games, in all cases by one goal, and they needed extra time to edge past their last-16 rivals.

However, that may well be where their similarities end. Argentina are football giants and Messi is one of the world's best players, while Belgium's youngsters are arguably gaining experience without a lot of pressure to perform.

Messi has scored four goals so far in Brazil, and he has been man of the match in Argentina's four games. He has failed to deliver consistently impressive performances, but it remains true that he has emerged in the four matches to lead Argentina to victory.

Against Bosnia-Herzegovina, Iran, Algeria and Switzerland, Argentina's rivals have focused on defence and have kept Messi reined in, but in every one of those matches he found at least one instance to let his undisputed genius shine through. 

Admittedly in the last 16, against a solid Swiss defence, that moment came only in the 118th minute, as he dribbled past two rivals and assisted Angel Di Maria for the lone goal in the match. The task at hand for Belgium is to make sure that the genius stays in the bottle, and coach Marc Wilmots believes they can do it.

"If Messi is in extraordinary form, he will give us problems. But if you ask me as coach whether I prefer a good collective or one great player, I prefer the team," Wilmots said.

Argentina have long relied on their "Fab Four" up front, but Gonzalo Higuain has underperformed so far in Brazil and so has Sergio Aguero. Against Belgium, with Ezequiel Lavezzi probably standing in again for the injured Aguero, Messi and Di Maria could do with a bit more help.

The World Cup has shown Argentina's weaknesses in defence. They have managed to concede three goals against sides that barely attacked, and they came dangerously close to conceding a lethal fourth: Swizerland's Blerim Dzemaili hit the woodwork just before the final whistle in extra time.

Belgium have only conceded two goals, and their problems do not appear to lie with a defence led by Daniel van Buyten and Vincent Kompany. They have played well and created many chances, but the fact that they have wasted a very large number of them remains a cause for concern.

US keeper Tim Howard had a great match and made 15 saves against the Belgians, but as Wilmots's men advance in the tournament more efficiency would serve them well.

"Obviously it will be a tough game," Wilmots said on Thursday. "But our aim is to stay. We have the potential to keep them busy and to produce a surprise."