OKLAHOMA CITY — In his first year as head coach, Jay Miller has the U.S. softball team once again dominating the competition.

Lauren Lappin homered off former University of Hawai'i pitcher Justine Smethurst to start a three-run rally in the third inning, and the United States beat Australia, 3-1, last night in the World Cup of Softball championship game.

Coming off a loss in the gold medal game of last year's Olympics, the Americans have won their first 20 games this year with a roster featuring 10 rookies — enough to outnumber the veterans.

The U.S. (6-0) outscored opponents 51-4 and, fittingly, got its toughest test in the finals.

"Every time we take the field, we don't just want to win. We want to dominate," said two-time Olympian Cat Osterman, who got the save with 1 2/3 scoreless innings. "We want to set a standard. The rookies are jumping right in the boat and going with us on that one."

Alissa Haber and Andrea Duran followed Lappin's homer with RBI singles to push the lead to 3-0, and Monica Abbott and Osterman combined to make it stand up for the Americans' third straight World Cup title.

Australia shortstop Stacey Porter, another former University of Hawai'i player, homered off Abbott. Porter was 2 for 3.

"This team can get a lot better. That's what's sort of scary and exciting at the same time, to see the potential that we have," said Miller, who took over for Mike Candrea, who stepped down after the Olympics. "Now it's our job to get them there."

It took some help from the few remaining veterans to get past Australia (3-3), which beat 2008 Olympic gold medalist Japan on its way to its first championship game at the World Cup.

Lappin, an Olympian last summer and an alternate in 2004, got the Americans on the board with her first home run in 16 games this year. Her drive off Smethurst just cleared the right-field fence.

Then Osterman, who played on each of the last two Olympic teams, came in to close the door when Abbott ran into trouble. She entered with runners on first and second, and struck out Danielle Stewart and Jodie Bowering to end the sixth inning.

With the tying run on first base, Osterman got Kylie Cronk to line out to right field to end the game.

"You saw a lot of character and a lot of heart and a lot of fight," Miller said. "You need games like this to sort of see what you're made of, to see where we're at."

Smethurst pitched three inning, allowing three earned runs, five hits, while strking out three and walking two.

Australia left fielder Clare Warwick, a former Rainbow Wahine, was 1 for 2. Kaia Parnaby, an incoming UH freshman, also was on the Australia team, but did not pitch in the final game.

CANADA 4, JAPAN 1

College softball player of the year Danielle Lawrie finished a shaky World Cup with a four-hitter as Canada claimed third place.

Jennifer Yee set a World Cup record with her fourth home run as the Canadians (4-2) jumped out to a 3-0 lead after three innings.

Haruna Sakamoto, who hit a grand slam off Lawrie a day earlier to knock Canada out of contention for the championship game, had an RBI single in the fourth for Japan (3-3).

NETHERLANDS 8, ITALY 1

Nathalie Timmermans drove in three runs and four other Dutch players homered as the Netherlands won the fifth-place game.

Natalie Gosewehr opened the bottom of the first with a homer, and Virginie Anneveld and Chandal Versluis added home runs in a five-run fifth inning for the Netherlands (2-4).

The mercy rule was invoked when Saskia Kosterink hit a solo shot with two outs in the sixth.

Italy finished 0-6.