In an upset as historic as it was inevitable, Tim Duncan (search), Allen Iverson (search) and the rest of the U.S. basketball team lost 92-73 to Puerto Rico (search) on Sunday, only the third Olympic defeat ever for the Americans and first since adding pros.

It was also the most lopsided loss in the games for the U.S. team, alarming not only for its significance but also for its decisiveness.

The Puerto Ricans, which had lost to the Americans five times in the past 13 months, led for more than 33 minutes of the 40-minute game. Theyd gamely held off a fourth-quarter comeback for one of the biggest sports achievements in the island territory's history.

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

Still, the defeat will go a long way toward giving the competition the bold idea that it's someone else's turn to move to the top of a sport that's been dominated by one country for nearly three-quarters of a century.

As Carlos Arroyo (search) left the court with just over a minute left, he defiantly pulled at the words "Puerto Rico" on his jersey. He led his team with 24 points.

Anyone in America who didn't see this coming hadn't been paying attention to the way international basketball has been changing. The U.S. team nearly lost in the semifinals at Sydney on a last-second miss 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 the defections and rejections of 12 top players, 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 their vulnerability to a tight zone defense was clearly exposed.

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

After Lamar Odom made their first 3-pointer, the Americans missed 16 straight. They tried to get the ball inside, but Puerto Rico collapsed several defenders into the paint and took the U.S. team's best player, Duncan, out of the offensive equation.

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 their two losses to the Soviet Union in the 1972 gold medal game and the 1988 semifinals.

They handled the loss to Puerto Rico with grace, congratulating their opponents and joining them in a huddle at center court before both teams exited to a standing ovation.

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

After Odom's 3, the first U.S. basket, Puerto Rico backed off and dared the Americans to hit from long range. They didn't, missing eight 3s over the rest of the quarter to trail 21-20.

When Duncan and Iverson sat down in the second quarter, Puerto Rico simply outclassed the Americans' young reserves.

A 3-pointer by Eddie Casiano was followed by an airball from the corner by Dwyane Wade. A layup by Jose Ortiz off a nifty no-look pass from Carlos Arroyo was followed by a jumper from Carmelo Anthony that wedged itself between the backboard and rim.

Arroyo drove past two defenders for a layup that made it 35-22, and the Americans were suddenly on their heels.

The Americans kept launching 3s, still to no avail, and Puerto Rico kept pushing the ball to the basket and pulling away.

A free throw by Arroyo made it a 20-point game, 47-27, and Iverson followed by missing a 3. Roberto Hatten scored on a drive to make it 49-27, and the Americans threw the ball away with a chance to hold for the last shot of the half.

Whistles and jeers greeted the Americans as they emerged from the locker room after halftime, but the crowd gave them some support when they tried to get back in the game in the third quarter. But for each small step the U.S. team took toward coming back, Puerto Rico had an answer. And compounding their troubles, the Americans kept making mistakes.

Iverson threw an alley-oop pass into the third row of the stands, and Arroyo hit a jumper to restore a 20-point lead. Duncan lost control of the ball and watched it squirt beneath his legs, and Puerto Rico turned it into a 4-on-1 break for a 62-41 lead.

A foul shot by Duncan with 6:11 left finally got the deficit under double digits, 69-61, but a missed jump hook by Richard Jefferson led to a layup by Arroyo and a three-point play for a 78-66 lead.

The Americans never threatened again, and a pair of breakaway layups by Rolando Hourroutiner off the U.S. team's misses sealed it.