ATHENS, Greece - Greetings from the Olympic men's basketball tournament, where America is tied for last place with Angola, Australia, New Zealand, China and the defending world champions from Serbia-Montenegro.

Yes, it was quite a first day.

"Never say never. Anything can happen," Allen Iverson said after the United States lost for only the third time in its Olympic history in a humbling and humiliating 92-73 thumping by Puerto Rico that should end all doubt about whether the rest of the world has caught up with America.

Other nations certainly have, and it was all on display for anyone who still needed convincing.

Sunday's most shocking result came as whatever remained of America's aura of invincibility slipped away in a lopsided loss that left the U.S. coach embarrassed and angry.

Tim Duncan, Iverson and the rest of the U.S. team fell behind by 22 at halftime to a team they had always dominated, and the best they could do in the second half was pull within nine for their first-ever Olympic loss with a team of professionals.

"No one's in awe. Everyone wants to come out and play their best game against us. That's the spirit of the Olympics," U.S. forward Lamar Odom said. "You shouldn't feel bad for us. You should feel good for Puerto Rico."

The day's most exciting finish came in a rematch of the gold-medal game from the 2002 World Championships when Manu Ginobili of Argentina barely beat the buzzer with an off-balance bank shot from 12 feet away for an 83-82 victory over Serbia-Montenegro.

In other games, Spain looked very impressive in an 83-58 victory over China, Greece topped Australia 76-54, Lithuania got past Angola 78-73 and Italy edged New Zealand 71-69.

Play resumes Tuesday, with the Americans suddenly filled with self-doubt heading into a game against a Greek team whose fans filled the Helliniko basketball complex with roars of delight in the night's final game.

The Americans' loss was a blow to the their confidence, but it did little to hurt their medal chances. They need only to finish in the top four of their six-team group to reach the quarterfinals.

"Obviously, we are the favorites to win the whole thing," Iverson said. "We have the NBA players, so it is a tough loss, but the only thing you can do is learn from the things we did wrong and try to make it better the next game."

Puerto Rico had a couple of NBA players, too, and one of them - Carlos Arroyo - was the best professional on the court with 24 points. As he exited the game with just over a minute left and the victory well in hand, he defiantly pulled at the words "Puerto Rico" on his jersey.

"That was him telling his island of 4 million people he was very proud to beat the big colossus from the north," Puerto Rico coach Julio Toro said.

It was by far the worst Olympic defeat ever for the U.S. men, and having it happen against a team they had dominated five times in the last 13 months only made it hurt worse.

"I'm humiliated, not for the loss - I can always deal with wins and losses - but I'm disappointed because I had a job to do as a coach, to get us to understand how we're supposed to play as a team and act as a team, and I don't think we did that," Larry Brown said.

Puerto Rico led for more than 33 minutes of the 40-minute game and held off a fourth-quarter comeback for one of the greatest sporting achievements in the territory's history.

"We're a small island with a big heart," guard Elias Ayuso said.

Anyone in the United States who didn't see this coming hadn't been paying attention to the way international basketball has changed.

The U.S. team nearly lost in the semifinals at Sydney on a last-second shot by Lithuania, then dropped three games on its home turf at the 2002 World Championships in Indianapolis - the first losses ever by a U.S. team of NBA professionals.

This year's team, weakened by defections and rejections of 12 top players, had opened its pre-Olympic tour of Europe with a 17-point loss to Italy and a last-second victory over Germany - a pair of games in which its vulnerability to a tight zone defense was clearly exposed.

Puerto Rico exploited that weakness, too, and the Americans could do next to nothing against the defensive strategy.

American teams had been 24-0 since the professional Olympic era began with the 1992 Dream Team, but now there is a blemish on their record to go with two losses to the Soviet Union in the 1972 gold medal game and the 1988 semifinals.

The U.S Olympic team's record now stands at 109-3.

Argentina 83, Serbia-Montenegro 82

Ginobili's shot left his hand just a split-second before the final buzzer, dropping through the basket to give Argentina a thrilling victory.

"Once it left my hand, I knew it was good," he said. "This is a very special thing."

Ginobili scored 27 points for Argentina, which avenged a defeat in the title game at the 2002 World Championships. This time, Argentina prevailed after a final 10 minutes that had all the excitement of a medal-round match.

Neither team led by more than four points in the fourth quarter after Serbia-Montenegro came back from a big early deficit.

AP-ES-08-16-04 0102EDT