Water polo is the Olympic equivalent of an upstairs-downstairs play: Everyone acts more-or-less polite and sporting above water, but underneath, the game’s brutal nature is revealed.

The scene underwater at the Olympics wouldn’t be out place in a Navy Seal training video. Players punch, kick, wrestle, elbow, and grab with impunity, their actions hidden from the referees on deck by splashing.

Historically, America has fared poorly in this physical game. The U.S. has tended to field teams that looked and performed like swimmers – a natural mistake in a game played in a pool 12 feet deep – instead of the ferocious aqua-gorillas stocked by the Eastern European powerhouses. The resulting games were uncomfortable to watch, like witnessing your uncle drown a litter of unwanted kittens.

America’s last Olympic gold was at the 1904 St. Louis games, when the field was crowded with American club teams and the game was played with a half-inflated ball; the last U.S. Olympic medal was a bronze in 1988. After a disappointing sixth-place showing at Sydney, the U.S. national program hired the game’s most celebrated coach, Ratko Rudic of Yugoslavia, to turn things around.

Rudic promises gold by 2008, but this year’s Olympics serve as a kind of midterm report. With only three returning Olympians, he couldn’t guarantee the best team in the tournament, but he could guarantee the fittest.

Rudic’s purportedly grueling two-a-day regimen has produced a U.S. men’s team that looks like it was drawn by a DC comic book artist: impossibly broad across the shoulders and chest, with tiny waists and legs, and chiseled jaws. Just as important, the Americans now wear the same hardened Easternbloc scowl as their opponents. One that says, in any language, “I give as good as I get.”

The difference shows in the water as well. The U.S. placed a strong second behind Serbia-Montenegro in the pre-Olympic Belgrade tournament earlier this month, then won its first game of the Olympics Sunday against a physical Croatian team.

The U.S. got out to a sizable lead early, but Croatia battled back, setting up a dramatic game-winning goal by America’s Tony Azevedo from the left side as time expired.

The men’s water polo team plays Kazakhstan tonight.