Puerto Rico’s Win an Inside Job : World Basketball: U.S. is no match on the front line in 81-79 defeat.

Puerto Rico dominated inside and defeated the United States, 81-79, Wednesday in a battle of unbeaten teams in the World Basketball Championships.

Both teams already qualified for the semifinals. The United States will play Yugoslavia, top-seeded in the other group, Friday, and Puerto Rico will play the Soviet Union.

Yugoslavia clinched a semifinal berth with a 77-67 victory over Greece. Velimir Perosovic scored 17 points, and Toni Kukoc, second-round draft choice of the Chicago Bulls, had 13. Valeri Tikhonenko scored 38 points in the Soviet Union’s 110-100 victory over Brazil.

The United States held a 73-68 lead with 7:34 to play, but went scoreless for almost six minutes as Puerto Rico took a 76-73 lead.

The United States broke the scoring drought on a rebound basket by Chris Gattling with 1:47 left and two free throws by Gattling 23 seconds later for its final lead of the game.

George Torres hit a three-point basket with 1:04 left to give Puerto Rico the lead for good. Billy Owens of the United States missed two free throws with 43 seconds left.

Jose Ortiz, who had 22 points and 10 rebounds, scored on a dunk with 25 seconds left to give Puerto Rico a four-point lead. Gattling hit a jumper with 11 seconds left on the United States’ final possession.

“When you have fast-break chances, you have to convert them,” U.S. Coach Mike Krzyzewski said of the several opportunities his team had during the drought. “When we missed, they got the rebound because their pursuit of the ball was very good.”

The United States couldn’t handle Puerto Rico’s front line, which combined for 51 points and 31 rebounds, 18 on the offensive end.

In addition to Ortiz, who played at Oregon State and with the Utah Jazz, Jerome Mincy, who played at Alabama Birmingham, had 17 points and 11 rebounds, and Ramon Rivas, who played at Temple and with the Boston Celtics, had 12 points and 10 rebounds.

Kenny Anderson had 20 points and five assists for the United States. Owens scored six points.

Guard Raymond Gausse, who scored 13 points for Puerto Rico, said the physical international style had a lot to do with the victory, which made his team 3-0 in the quarterfinal round and 6-0 overall.

The United States defeated Puerto Rico, 100-94, in the opening round of the Goodwill Games last month.