BEIJING, Aug. 13 (Xinhua) -- Cat Osterman tossed a perfect game here on Wednesday when three-time defending champions the United States beat Australia 3-0 at the Beijing Olympic softball tournament.

    The left-handed pitcher Osterman worked seven complete innings for her first start of the tournament, striking out 13 batters and allowing no hits.

    Cat's Aussie counterpart Tanya Harding also did an outstanding job in the circle.

    The right-handed hurler only surrendered three hits in the first four innings and allowed no runs, yet failing to block the explosion from American's batters in the fifth.

    Natasha Watley's single in the bottom of fifth inning drove Lovieanne Jung home to give the American's opening run.

    And Slugger Crystl Bustos delivered a two-run homer in the sixth to edge the lead to 3-0.

    The U.S. has met up with Australia in the 2005 and 2006 World Cups, coming out with a 5-1 and 9-0 wins respectively. But in American's lone four Olympic losses, two of them have been to Australia and ace pitcher Harding recorded the win in both.

    The Aussies will face host China on Thursday after surrendering two straight losts. While the U.S. "Dream Team" with two wins in pocket will play Canada.