Li Na from China ousted Venus Williams of the United States in the women's singles quarterfinals at the Olympic Games on Thursday.
Li knocked out Williams at 7-5 and 7-5 in two hours and seven minutes.
Li, a former world top 20 player who came into the Olympics unseeded, had beaten Russian third seed Svetlana Kuznetsova in the first round of the event.
In an early match, Serena Williams, Venus' younger sister, was also knocked out from the quarterfinals after losing to Russian fifth seed Elena Dementieva.
(Xinhua News Agency August 15, 2008)