A lot of people are rooting for the U.S. -- not least the world's book-makers, who see American fans as a rich, untapped market.
"This is the single biggest betting event in history," says Jon Ivan-Duke of Britain's William Hill Bookmakers.
The World Cup is a bookie bonanza. Ivan-Duke says, "200 million pounds will be turned over this World Cup."
That's pushing 350 million dollars. And that's without the U.S., where betting is only legal in a few states.
If Americans can learn to love soccer, the bookies are betting they can learn to love putting a few bucks down on the game as well.
"If those laws were to be relaxed across the states ... then we're ready and raring to go, really," explains Ivan-Duke.
In a statistics-mad country like the U.S., the bookies think their newest fad has "America" written all over it.
Uruguay's Louis Suarez would bite someone -- and paid up when he did.
The biggest bet placed on the World Cup so far was from an American. "This particular customer in our Nevada sports book shop put a bet of $320,000 on Argentina to beat Iran," says Ivan-Duke.
In that game, Argentina won on a last-minute goal.
The current odds for the U.S. to win the World Cup are 80 to 1.