Okay, now for the hard part.

Team USA completed its domination of the preliminary round of the Olympic men’s basketball tournament yesterday with a 106-57 annihilation of Germany. The U.S. was the only unbeaten team, going 5-0 with an average victory margin of 30 points, and no opponent could stay within 20.

And for that they get … absolutely nothing.

When the quarterfinals tip off tomorrow, everybody is 0-0. Should the Americans lose, they won’t even end up with a medal — as happened to Spain in 2004, after they went unbeaten in pool play.

After the 2006 semifinal loss to Greece at the World Championships, the U.S. team appears to understand this — especially veterans of that defeat, such as LeBron James, Dwyane Wade, and Carmelo Anthony.

First up will be Australia, which closed its pool play with a bang by blowing away previously unbeaten Lithuania, 106-75. Australia gave the American squad its toughest test of the summer during a tune-up game before the Olympics, rallying to within seven points in the fourth quarter before losing 87-76. They kept it close despite not having their lone NBA player, Milwaukee Bucks center Andrew Bogut, available for the contest.

Bogut is the Aussies’ leading scorer and rebounder, and Bucks observers will be shocked to learn he’s felt free to launch from the shorter international 3-point line — he’s made five of seven in the tournament. Australia as a whole has made 44.4% of its 3-point tries, so it’s very important for the U.S. to chase them off the line.

Australia’s second-best player is guard Brad Newley, a second-round pick by the Houston Rockets two years ago who plays professionally Down Under. He’s 8-of-15 on 3s in the tournament and a scalding 65% from the floor overall; look for U.S. defensive ace Kobe Bryant to get the assignment against him out of the gate.

The third double-digit scorer for Australia is Patrick Mills, who plays collegiately for St. Mary’s in California. The 5-foot-11-inch indigenous Australian is the speed demon on what is otherwise a rather slow team, and his ability to carve up the U.S. defense on penetration helped keep Australia close in that tune-up game.

Australia has a few other weapons behind them. Seven-footer Chris Anstey played for the Dallas Mavericks back in the day and has a nice touch at the offensive end, while power forward David Andersen is a star for CSKA Moscow in Europe with a nice mid-range game.

Nonetheless, one wonders if the worst thing Australia could have done was to play the Americans close two weeks ago in Shanghai. The biggest thing going for any team hoping to upset the U.S. is the element of surprise, that they might be underestimated and catch the more talented American side unawares. That no longer appears to be a possibility based on that first matchup.

Just to review, Australia kept the game close by forcing the U.S. to play a half-court game and watching as the Americans made just 3-of-18 from the 3-point line and just 20-of-33 from the free-throw line.

A big, physical team, Australia will be challenged to get back on defense and cut off the fast breaks that have fed the U.S. offense, but one key will be reducing turnovers. Australia only had 18 in the last meeting, which is actually an impressive total against a U.S. side that has forced 22.6 a game, including a whopping 53 in the two games against medal contenders Greece and Spain.

Clearly, the American game plan will be to get the ball out of the hands of Mills and force Australia’s other players to handle the ball and play at a faster pace than they’re accustomed. The challenge is to do this while not opening the 3-point line, where the Aussies have dissected the opposition all tournament long.

It’s also worth nothing that while Australia defended the U.S. effectively in Shanghai, they haven’t stopped anybody in Beijing. For the tournament as a whole they’re allowing 51.3% shooting and an almost absurd 46.4% on 3-pointers; even their wins have been largely the result of superior offensive efficiency rather than anything brilliant they did on D.

Given how well the American side has played the past three games, I expect them to dissect Australia’s defense much more effectively than they did back in Shanghai. Look for the U.S. side to break triple digits in this one and roll into the semifinals.

Meanwhile, we have three other quarterfinals to dissect tomorrow:

Greece (3-2) vs. Argentina (4-1): If America advances, it plays the winner of this game in the semifinals, and either way the Americans should have revenge on their minds. Argentina knocked out the U.S. in the semis en route to winning the gold medal in 2004 in Athens, while Greece upset the U.S. in the semis of the World Championships in Japan two years ago.

Americans should root for the Greeks, whom the U.S. already handled by 23 points in pool play, because Argentina is much more dangerous — not to mention the only medal contender the U.S. hasn’t humiliated this summer. Argentina gained steam after losing its Olympic opener to Lithuania in the final minute, winning its last four contests by double digits, and San Antonio Spurs star Manu Ginobili has picked up his play noticeably as he recovers from an ankle injury. I’ll take Argentina to win by a dozen.

Spain (4-1) vs. Croatia (3-2): Viewed as the main contender to the U.S. for the gold medal, Spain hasn’t played particularly well in this tournament and I’m not completely convinced the coach knows what he’s doing. Aito Garcia Reneses replaced Pepu Hernandez a month and a half before the tournament, and his playing rotations and strategies thus far have been bizarre. We’ll see if he can bring some sense to the affair in the elimination round. Meanwhile, Croatia has already overachieved by making it this far and seems unlikely to continue its good fortune against the defending world champions.

Lithuania (4-1) vs. China (2-3): Don’t rule out an upset here. Though Lithuania won Pool A, they lost to Australia by 31 yesterday and the Chinese will have home-court advantage in Beijing. Yao Ming should dominate inside, but it’s two points for him and three for the Lithuanians, who hit 49.5% from downtown in pool play. The Chinese need cold shooting from Lithuania in order to make the semis and face the Spain-Croatia winner. I’m guessing they’ll battle heroically and end up losing by seven.

jhollinger@nysun.com