SANTO DOMINGO, Dominican Republic -- For the second straight Pan Am Games, the Brazilians knocked the American men out of gold medal contention.

Two second-half runs carried Brazil past the United States 92-80 in the semifinals of the Pan American Games on Tuesday.

"I think we played well for 3½ quarters, but we didn't close it out,'' U.S. coach Tom Izzo said. "We got what we deserved, and they got what they deserved. Turnovers down the stretch killed us.''

Marcelo scored 22 points and Guilherme added 19 as the reigning Pan Am champions sent the Americans into the bronze medal game.

Connecticut's Emeka Okafor led the U.S. team with 18 points and Kentucky's Chuck Hayes added 15.

Brazil will face the Dominican Republic, and its raucous fans, in the gold medal game. The host nation defeated Puerto Rico 79-65 in Tuesday's other semifinal. The U.S. team will play Puerto Rico for the bronze on Wednesday. The Americans lost to Puerto Rico 86-85 last Sunday in group play.

Hayes tipped in a rebound with 4:18 remaining in the fourth quarter to give the U.S. team a two-point lead. The Americans didn't score again until it didn't matter.

Brazil answered with a 13-0 run, which was spurred on by seven points from Marcelo. The Brazilians' tight half-court defense rattled the Americans, who had few good looks at the basket in the last four minutes.

"We didn't execute,'' Okafor said. "They made it very difficult down the stretch and we did not respond. It's tough, because we played so well, but you can have one bad quarter and lose the game.

"Now we have to focus on bringing home a medal.''

The pace of the first quarter was faster than the samba beat coming from the Brazilian drummers in the stands. Both teams rushed the ball up the court as five hurried possessions failed in the first 45 seconds.

When things settled down a little, the Americans' crisp ball movement, which had been lacking to that point in the tournament, and fast breaks opened an 11-point lead midway through the second quarter. Their defense flummoxed the Brazilians, forcing them to heave low-percentage 3-pointers.

The stifling American defense held Marcelo scoreless in the first quarter.

Brazil cut the lead to six at the half, but Team USA was up 11 again early in the third period. The Brazilians answered with a 20-8 run and led by one going into the fourth.

"We did everything we wanted to do, we just didn't finish plays at the end,'' Michigan State's Izzo said.

In 1999, a team of CBA players was beaten by Brazil for the gold medal in Winnipeg.

The American men have not won a gold medal since 1983 -- when the team included Michael Jordan, Chris Mullin and Wayman Tisdale.

The U.S. women clinched a spot in the semifinals with a 93-78 win over Argentina. Rebekkah Brunson of Georgetown and Loree Moore of Tennessee scored 12 points each for the Americans.