So far none of Argentina's opponents has been able to stop Lionel Messi.
Perhaps Belgium has what it takes. But even if doesn't, the Red Devils present a fresh challenge for Argentina at this World Cup.
For the first time in Brazil, Argentina faces an opponent with attacking potential that rivals its own.
''We will have to adapt, but what really interests me is to see how they will adapt to us,'' Belgium coach Marc Wilmots said.
Argentina has struggled on its road to the quarterfinals, relying on single moments of Messi magic to break stalemates against mostly defense-oriented teams.
On Saturday in Brasilia, it's up against a young, sparkling team that's considered a dark horse for the title. Even though it needed extra time to prevail against the United States, Belgium unleashed offensive qualities in that game that could present major problems for Argentina's at times shaky defense.
Belgium fired 38 shots, half of them from midfielders Kevin de Bruyne and Eden Hazard, and strikers Divock Origi and Romelo Lukaku. An impressive performance by U.S. goalkeeper Tim Howard kept the score down.
Meanwhile, Argentina's attack hasn't been as fearsome as predicted. Center forward Gonzalo Higuain is scoreless after four games and his attacking partner Sergio Aguero is out injured. Ezequiel Lavezzi is replacing the Manchester City striker but was largely ineffective against Switzerland.
Then there's Messi.
The little genius has delivered when Argentina needed him most, scoring in every group stage match and setting up Angel Di Maria's extra-time winner against Switzerland in the round of 16.
In a tight game, the Swiss shackled him successfully until his decisive run in the 118th minute.
''We knew that we would face a situation like that, but that's football and we had luck on our side,'' Messi said. ''We're aware that all matches are going to be very close and that details will make the difference.''
Wilmots was unwilling to compare the strengths of the two teams but noted that except for a few players, Argentina's performance at the World Cup has exposed some weaknesses.
''Obviously they have Di Maria, Lavezzi, Higuain and Messi,'' Wilmots said. ''But I also saw they showed a lack of balance within the team and that they had problems.''
If Messi is in extraordinary form, he will cause problems for Belgium, Wilmots conceded Thursday. ''But if you ask me as a coach whether I prefer a good collective or one great player, I prefer the team.''
Argentina left back Sergio Rojo is suspended and will probably be replaced by Jose Basanta in Saturday's game.
Wilmots said Belgium left back Thomas Vermaelen is likely to return after missing the U.S. game with a hamstring injury, while midfielder Steven Defour is back from suspension.
Belgium and Argentina haven't met in the World Cup since the 1980s, when they were both at their peak.
In 1982, Belgium beat Argentina 1-0 in their World Cup opener. Four years later Diego Maradona scored both goals in a 2-0 semifinal win on Argentina's road to its second World Cup title.
Associated Press writer Raf Casert in Mogi Das Cruzes, Brazil, contributed to this report.
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