Jessica Mendoza hit a homer to help United States render Canada the first defeat by 4-0 in Women's Softball World Championship here on Tuesday.

US starter pitcher Berg Laura struck out ten all through the match frustrating Canada offense a lot, allowing three hits only.

After two scoreless innings, United States hit three straight singles to drive Warley Natasha home step by step to claim the first run of the game.

Berg Laura batted one-run triple in fourth to send Jung Lovieanne home then she had home run in seventh to score two runs for the defending champions.

Canada starter Risin Mackin gave off a walk to Duran Andrea followed by two singles from Jung Lovieanne and Laura Berg to give Duran Andrea another home plate.

The United States got nine hits against three by Canada.

"We don't expect to beat United States before the game. United States is the defending champions and we put our eyes on tomorrow against DPR Korea," said Lori Anne Sippel, Canada coach.

"Our target here is to reach the last four which can ensure us a spot in Beijing Olympics," added she.

"They got a powerful pitcher to strike out ten all through the match, so we can not turn out effective offense. I think it will be different if we got the ten opportunities."

US coach said his team played an outstanding game and their pitcher Berg Laura is great to beat any team if she continue to play in this way.

The World Softball Championship is the first Olympic test event in Beijing with 16 teams competing in two pools, which will produce four spots (excluding China, the host) participating in the Beijing 2008 Olympic Games.

The 2008 Olympic softball tournament will be the last for at least eight years. Softball first featured as a medal sport at the Atlanta Olympic Games in 1996, but it was removed from the Olympic events for 2012 London Olympics.