World Cup on Tuesday: Argentina takes on Switzerland

Where: Sao Paulo. Time: 9 a.m. PDT. TV: ESPN, Univision.

The buzz: After years of criticism that he can't win the big ones, Argentina's Lionel Messi has been on a mission in this World Cup. He scored the deciding goal in Argentina's first victory, had the only goal of the game in stoppage time in the second contest then had two goals in the final group-play game. That will make him the focus of the Swiss defense, a task made easier by the loss of striker Sergio Aguero, who is out because of a leg injury. Aguero probably will be replaced by Ezequiel Lavezzi. But if Messi and Argentina, the world's No. 5 team, have been running roughshod in Brazil, the same can't be said for sixth-ranked Switzerland. The Swiss needed a victory over Honduras to escape group play and the six goals they have given up is the most by a team in the knockout round. Xherdan Shaqiri had a hat trick against Honduras. Switzerland will be without forward Mario Gavranovic, who tore the anterior cruciate ligament in his right knee during training Saturday.

The buzz: Belgium is one of four teams that won all three of its games in group play. But the Belgians, playing against poor competition, didn't look good doing it. Thibaut Courtois is one the best goalkeepers in the world. But Belgium showed little spark offensively and it is crippled on the back line. The availability of top central defender Vincent Kompany, slowed by a groin problem, won't be made until game time and two other defenders, Thomas Vermaelen and Anthony Vanden Borre, are definitely out. The U.S. won only one of three games in group play, but it led Portugal until the final minute, then held powerful Germany to a goal in a loss. The return of Jozy Altidore from a hamstring strain could help a U.S. attack that, statistically, is the worst of the 32 World Cup teams, behind even Iran and Honduras. But he's unlikely to play, so to break down the Belgium defense the Americans will have to create some options beyond Clint Dempsey and Jermaine Jones. Will this be the game in which Michael Bradley breaks through? With Omar Gonzalez back in the lineup, the U.S. backline played much better against Germany. Tim Howard has been solid, if not spectacular, in goal.