-- The U.S. men's basketball team, which had not lost an Olympic game since it began using professional players 12 years ago -- and only twice in the Games since 1936 -- was soundly beaten Sunday night at Helliniko Indoor Arena by Puerto Rico, a historic outcome that signaled the end of America's unchallenged dominance in a sport that was invented and perfected in the United States.

The precursors for the 92-73 blowout loss were many, yet for the U.S. fans who waved American flags in the waning moments, desperate for a comeback, it was still shocking. The United States had won 109 of 111 previous Olympic games. Since professional players from the National Basketball Association were first invited in 1992, the United States was a perfect 24-0.

The loss, while historic, did little to dim the Americans' medal chances. They play four more games -- including a meeting Tuesday night against the host country that is sure to draw a crowd of wildly partisan Greeks -- before the field is winnowed from 12 to eight.

But the implications of the loss -- and the message sent to other hopefuls in the field -- were obvious. Puerto Rico, with only two NBA players, wasn't considered a serious threat for a medal. Yet the manner in which the game played out, with U.S. players complaining to officials and slumping on their bench, left Coach Larry Brown saying he was "angry" and "humiliated."

"I think these guys played the game the way it's supposed to be played," U.S. guard Allen Iverson said of Puerto Rico. "They think the game out."

The last U.S. loss in the Olympics came in 1988, when a group of college players lost to the Soviet Union in the semifinals and settled for bronze. The only other time the United States failed to sweep all its games and win gold was in 1972, when the Soviets took a controversial victory in which replays showed the clock had expired when the Soviets hit the winning shot in the gold medal game.

The team competing here is by no means the first choice of organizers. Fourteen players -- including NBA stars such as Kobe Bryant, Shaquille O'Neal and Kevin Garnett -- couldn't or wouldn't play because of injuries or other conflicts. Others turned down the opportunity because of concerns for their security in Greece. Already, there was a marked contrast with the old days of the "Dream Team," the squad the United States sent to Barcelona in 1992, when luminaries such as Michael Jordan, Earvin "Magic" Johnson and Larry Bird joined together and made other high-caliber players clamor for the opportunity to play alongside them.

Since the "Dream Team" stormed to the gold in Barcelona -- winning by an average of more than 40 points, then being begged to pose for photographs by their opponents -- international basketball has improved drastically. European players dot NBA rosters. Buoyed by the fact that they can play at the highest level, those players are starting to spread the word to their countrymen: The USA is not indomitable.

"To tell you the truth, it's not like before," said Puerto Rico's Carlos Arroyo, who plays for the Utah Jazz and was the star of the game with 24 points. In years past, "you play U.S., it automatically is a loss, because you're playing the best players. You have to admit the reality.

"But the fact is, we've got good players, too, and we're not intimidated."

Such evidence has become plain since the last Olympics, when an occasionally uninterested group of NBA players narrowly averted a last-second loss to Lithuania, but still won the gold. In 2002, playing on its home soil in Indianapolis, the Americans finished an inconceivable sixth at the world championships.

Then, since this team came together in late July for a brief training camp and exhibition tour, the signs were clear. The United States was handled easily by Italy, not considered a medal contender here, and needed a last-second shot by Iverson to defeat Germany, which didn't qualify for this tournament.

Still -- this?

"Not that expectations are unreasonable," U.S. forward Richard Jefferson said. "We should win the gold medal. We are the most talented. But it's tough when you throw players together in two weeks and tell them to become a team."

That was Brown's chief gripe afterward. One of the best coaches in the game's history -- the only one to win championships at both the college and NBA level -- his frustration over his team's attitude was palpable afterward.

"I don't know what we can get out of this game," he said, "because the first day we got together as a group, we talked about respecting our opponents, realizing that these guys have played together, realizing that the game has gotten better all over the world, and trying to understand how important it is for them to represent their country and play the right way. . . .

"I'm angry because the mentality of our team was like this from Day One. And now, we've got to coach them better, and we're going to find out if we're ready to truly become a team."

The game played out in startling fashion, with Puerto Rico seizing a 22-point lead at halftime. The United States clawed to within eight points in the fourth quarter, but its deficiencies were too pervasive. While Arroyo, the Puerto Rican point guard, was creative and careful with the ball, teammates Eddie Casiano and Elias Ayuso converted six three-pointers. That emphasized the Americans' greatest weakness, the inability to perform basketball's most essential fundamental -- shooting. They made just 3 of 24 three-point attempts.

"We couldn't hit a shot to save our lives," Jefferson said.

Now comes the daunting task, the task the U.S. players preferred to discuss afterward -- trying to regroup and pursue gold anyway. The Americans next play Tuesday against host Greece, when they are sure to face a nearly impossibly hostile crowd. Games against Australia, Lithuania and Angola will determine whether they advance to the quarterfinals. Awaiting there, where a loss would mean elimination without a medal, could be Argentina or Serbia and Montenegro, two of the pre-tournament favorites for gold.

Whatever happens over the next two weeks, history has already been made. "From our perspective," Brown said, "the only thing we can do is find out what we're made of."

Allen Iverson, left, and Tim Duncan can't believe their eyes as they watch the U.S. team fall behind by 24 points and lose to unheralded Puerto Rico, ending a streak of 24 straight victories by Olympic teams starring NBA players.Larry Brown exhibits his frustrations as his young U.S. squad is routed, 92-73.