Capsules for Saturday's matches at the World Cup (FIFA rankings in parentheses):
South Korea is in its seventh successive World Cup, while Greece has made one previous appearance, losing three games in 1994 without scoring.
South Korea: The Koreans went to the semifinals when they co-hosted the 2002 tournament, and have a star in Manchester United midfielder Park Ji-sung.
Greece: The 2004 European champions have not done much since winning that title, but a stultifying defensive style can wear down opponents.
Notable Fact: Greece center back Vangelis Moras will sit out after a groin injury, perhaps weakening the Greeks' chances.
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The Albiceleste might have the two biggest stars in the tournament: player of the year Lionel Messi and coach Diego Maradona.
Argentina: Maradona, something of a novice as a coach, is toying with starting three strikers, including the sensational Messi.
Nigeria: The Super Eagles were Africa's best team in the 1990s, but are not so formidable now. A younger squad lost 1-0 to Argentina in the 2008 Beijing Olympics final.
Notable Fact: Messi has been a dominant player for Barcelona, but never a standout for Argentina, with 13 goals in 44 matches.
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Few soccer games have gotten the amount of attention in the United States that this one has, and a U.S. upset win could provide a huge boost to the sport in America.
England: Captain Rio Ferdinand was lost to a knee injury in training, which puts more stress on veteran center back John Terry. But the key player is potent striker Wayne Rooney.
United States: This is the rare American team that can score, with creative midfielder Landon Donovan as the playmaker.
Notable Fact: The only time these nations met in the World Cup was 1950 — and the Americans won, 1-0. It's considered one of sports' all-time biggest upsets.
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