GAINESVILLE, Ga. (AP) _ Karen Kraft and Missy Schwen were sitting at the starting line Thursday when Schwen noticed an important piece of equipment hanging loosely.

``She almost lost her left kangaroo. I had to tell her to fix it,'' Schwen said.

Kraft, of San Mateo, Calif., quickly pulled the good-luck earring back into place, and the U.S. rowers defeated the defending world champion Australians in the Olympic women's pair semifinals.

The top three in the event advanced, so the Americans and Australians will face each other again Saturday in the finals.

The two U.S. women began wearing kangaroo earrings following four months of training in Australia this year with Megan Still and Kate Slatter, who beat the Americans in a race last September.

``This is her second pair (of earrings) because she lost the first pair when we won in Lucerne,'' said Schwen, of Bloomington, Ind.

They also picked up a new boat in Australia, a round-bottomed shell that can move faster than traditional boats. They consider each race a learning experience as they figure out how to maximize their speed.

``We have known all along (the Australians) would be the team to beat, so we were really excited to draw them in the semifinals and have the showdown,'' Schwen said. ``That was really significant.''

The Australians jumped out quickly, which Kraft and Schwen expected. Still and Slatter led by a third of a length at the halfway point.

``We knew we needed to hold them and then respond, and that's what we did,'' said Schwen.

Two of six U.S. boats racing in the semifinals qualified for the finals, with the top three finishers in each race advancing.

Ruth Davidon of Arlington, Va., will race Saturday after finishing second behind Denmark's Trine Hansen in the women's single sculls. Also advancing were Canada's Silken Laumann, who took the bronze medal in 1992 despite an injured leg, and Yekaterina Khodotovich of Belarus.

U.S. pair Michael Peterson and Adam Holland led their semifinal until the halfway point, but Peterson began struggling due to a combination of high blood sugar and lactic acid.

They failed to advance to the medal finals, finishing fourth behind winner Steven Redgrave and Matthew Pinsent of Great Britain. Peterson immediately sought treatment at the venue medical center.

``Michael is prone to large swings in blood sugar, and today it hit him,'' Holland said. ``We both gave it everything, and we just weren't quick enough.''