Bantamweight Gary Russell and featherweight Raynell Williams qualified for the Beijing Olympics with convincing victories and built on the US team's momentum at the World Boxing Championships on Tuesday.
Heavyweight Ihab Al Matbouli of Jordan collapsed in the ring during one of the final bouts of the night session. International Boxing Association spokesman Richard Baker said fatigue was the cause and that the fighter was not seriously injured.
He was expected to spend the night at Rush University Medical Center.
Al Matbouli had just taken a hit from China's Nijiati Yushan in the fourth round of their fight, one of the final bouts of the night. The referee ordered him to his corner, and the fighter fell backward.
That overshadowed what had been an up-and-down day for the US team.
While Russell and Williams won their bouts in the afternoon, things didn't go as well in the night session for Javier Molina and Shawn Estrada.
Molina, a light welterweight, lost 24-12 to England's Bradley Saunders in the round of 16, while Estrada dropped a tiebreaker to Germany's Konstantin Buga in their middleweight bout.
The top eight finishers in the light flyweight to light heavyweight divisions and the top four from the heavyweight and super heavyweight classes at this event reach the Olympics. There are two continental qualifiers next year, so this wasn't their final shot.
Russell outpointed fellow 2005 world bronze medalist Ali Hallab of France 22-14 in the round of 16, while Williams was leading 23-3 when his bout with Armenia's Azat Hovhannisyan was stopped in the third round.
No US boxer has won a gold medal at the worlds since 1999, but the US are now 18-5. It's a good position, but not quite as good as the Russians, who are 22-0 in this tournament.
Russell and Hallab both lost semifinal bouts in 2005 to get bronze, so they didn't have to face each other for back then. But they met this time with a spot in the Olympics at stake.
Hallab tried to outbox the quicker Russell through the first two rounds, but that didn't work. A right hand and a possible slip sent Hallab into the lower ropes in the opening round, and Russell led 8-3 after two. Hallab was the aggressor over the final two rounds, but 19-year-old Russell held his ground and countered.
Williams grabbed an 8-1 lead in the first round against Hovhannisyan and never looked back. He said everything was working for him, particularly his left.