Beijing, August 9:

Chinese athletes won two gold medals on a first day of Olympic competition marred by the stabbing death of an American volleyball coach’s relative and two doping controversies.

A knife-wielding Chinese man attacked two relatives of the coach at a tourist site in Beijing, killing one and seriously injuring the other, team officials said.

China quickly got on the gold medal tally board when Chen Xiexia won the women’s 48-kg weightlifting and 2006 world champion Pang Wei took the men’s 10-metre air pistol.

Katerina Emmons of the Czech Republic had the distinction of winning the first of 302 golds to be awarded before the games end on August 24 when she took the 10-metre air rifle.

Also, Alina Dumitru of Romania won women’s 48-kg judo gold and Choi Min-ho of South Korea took the men’s 60-kg class in judo. In fencing, Mariel Zagunis won the first gold medal for the United States, leading an American sweep in women’s saber.

There were also two positive doping tests involving Beijing-bound track athletes. The Greek national Olympic committee said 29-year-old sprinter Tassos Gousis, who competes in the 200m, tested positive for the steroid methyltrienolone on Monday. He was sent home from the training camp in Japan.

Russian steeplechase runner Roman Usov was pulled out of the games amid reports he failed a doping test conducted at the selection trials last month and only a week after seven female athletes from Russia were implicated in a doping scandal.

Samuel Sanchez of Spain won the gold medal in the grueling men’s cycling road race that took the 143 competitors from central Beijing past Tiananmen Square, the Forbidden City and other landmarks before they rode out of the city for seven laps of a hilly loop course between two points on the Great Wall.

Michael Phelps began his quest for a record eight Olympic gold medals in the pool when he broke his own Olympic record in qualifying for the 400m individual medley. The American won his heat in 4 minutes, 7.82 seconds, bettering his Olympic record of 4:08.26 set four years ago in Athens.

The defending champions United States edged Japan 1-0 to revive their chances of a third Olympic gold medal in women’s football and World Cup champions Germany beat Nigeria by the same score to move closer to a title they have never won. Nilla Fischer’s 57th-minute corner gave Sweden a 1-0 victory over Argentina.

Also, Brazil beat North Korea 2-1, Norway topped New Zealand 1-0 and hosts China earned a 1-1 draw with Canada.