BEIJING, China -- Already guaranteed a medal, but showing no signs of slowing down, the United States softball team cruised to a 9-0 rout of China on Monday.

Kelly Kretschman blasted a three-run homer to key a nine-run first inning for the Americans, who closed out an opponent in five innings for the fifth time in seven games at the Beijing Olympics.

The game was shortened by the international run-ahead rule.

The U.S. moved to 7-0 and on to the medal round, which begins on Wednesday.

Currently holding a 21-game Olympic winning streak that dates to Sydney in 2000, the Americans will be looking for their fourth consecutive gold medal in softball's last appearance in the Olympics until at least 2016.

The team makes no apologies for its dominance, with catcher Stacey Nuveman saying after Sunday's 8-0 victory over the Netherlands, "If we can get the win in early, we will."

Monica Abbott, who was perfect in the five-inning shutout of the Netherlands, compared the team to another example of Olympic dominance.

"If Michael Phelps can win eight gold medals, why can't USA softball?" she asked. "That's what Olympic competition is about. It's about giving the people at home chills."

Cat Osterman struck out three batters in three scoreless innings against China to run her record to 3-0, while Jennie Finch completed the game with two hitless frames.

The three U.S. pitchers -- Osterman, Finch and Monica Abbott -- have a 0.00 combined ERA in 39 innings pitched. The U.S. has outscored its opponents 53-1 in its seven games, with the only run allowed being an unearned tally by Canada last week.

"We're hitting on all cylinders," said Finch.

China's only hit was a single by Zhou Yi in the first inning. The Chinese have now scored just three runs in five games, but they are known more for defense and pitching than for offense.

Zhou's diving catch on a Lovieanne Jung fly ball to centerfield was a good example of that. China already trailed 9-0 at the time.