"I'm in the best shape I've ever been," said Nguyen. "I trained hard for this one."

Germany and Canada both won three gold medals on Thursday. For Germany, Levent Tuncat defeated Jermaine James (Cape Coral, Fla.), 5-1, in the men's flyweight division; Suemeyye Guelec beat Nicole Palma (Lake Worth, Fla.), 9-2, in the women's finweight class; and Helena Fromm defeated Marjolijn Abbink of the Netherlands, 5-1, to win the women's welterweight gold medal.

For Canada, Sebastien Michaud beat Rudford Hamon (Miami, Fla.), 3-1, to win the men's welterweight class; Anne-Pier Turcotte defeated Colombia's Gladys Mora in sudden death, 1-0, in the women's flyweight division; and Karine Sergerie won 6-1 over Joyce Von Baaren to capture the women's lightweight gold medal.

In the men's lightweight final, Puerto Rico's Juan Sanchez defeated Canada's Christopher Iliesco, 3-0.

Bronze medal winners on Thursday were: Gus Villa (Los Angeles, Calif.) and Domingo Rico (PHI) in men's finweight; Eric Phamhung (CAN) and Alex Sanchez (PAN) in men's flyweight; Chad Dahm (West Bend, Wis.) and Manuel Suarez (Miami, Fla.) in men's lightweight; Balazs Toth (HUN) and Anthony Barrow (CAN) in men's welterweight; Rachel Marcial (San Mateo, Calif.) and Angela Serapian (SWE) in women's finweight; Sandra Zenteno (MEX) and Melanie Hartung (GER) in women's flyweight; Nia Abdallah (Houston, Texas) and Sarah Cunningham (CAN) in women's lightweight; and Courtney Condie (CAN) and Nina Solheim (NOR) in women's welterweight.

The U.S. Open continues on Friday with competition in the bantam, feather, middle and heavyweight divisions, and runs through Sunday.