Arioto homered in her third straight game and drove in four runs, Samantha Fischer tacked on a three-run shot and the U.S. beat Canada 9-0 in five innings Saturday night in the World Cup of Softball.
"She's been on fire. It's unbelievable," Fischer said. "She's just hitting the ball everywhere. Where it's pitched, she's hit it hard, she's hitting it out and just producing a lot of runs and a lot of opportunities for us to score."
Arioto smashed a three-run home run to left-centre field off Marina Demore (0-1) in the first inning and added an RBI single in the third, just before Fischer homered — also to left-centre — to make it 8-0. Keilani Ricketts (1-0) gave up four hits and struck out six in a shutout as the game ended because of the run rule.
Arioto also delivered the tiebreaking solo home run in the bottom of the sixth inning earlier in the day to lift the U.S. to a 2-1 victory over the Netherlands. A night earlier, she opened the scoring with a solo homer against Australia in what ended up being a 3-1 win.
She is 5 for 9 with three home runs and six RBIs in four games in Oklahoma City.
"Valerie's definitely seeing the ball. If I was the other pitcher, I wouldn't be throwing to her," Ricketts said.
Arioto credited a strong scouting report and good anticipation and said, "I'm looking for a certain pitch and I've gotten it so far."
Coach Ken Eriksen credited her hard work after the end of the college season, when Arioto was the Pac-12 player of the year at California and one of three finalists for the national player of the year award won by Ricketts.
Eriksen said Arioto arrived at Team USA camp with her swing off-kilter because of a unnecessary movement in the lower half of her body, and she's been able to correct it to find her groove.
"If your eyes are steady and you're behind the ball with her type of power, the kid can get scary," Eriksen said. "And right now, she's scary."
Fisher put the U.S. (4-0) in position for a run-rule victory when she homered on the second pitch from reliever Karissa Hovinga. She also homered off of Hovinga in an exhibition last weekend marking the 40th anniversary of Title IX.
Melanie Matthews had two of the four hits for Canada (0-3), a single to leadoff the game and a double to start the third. But Ricketts stranded her in scoring position both times.
The U.S. faced its only deficit of the tournament in the early game after Nathalie Timmermans — who formerly played at Central Oklahoma and Oklahoma City University — homered in the fifth for the Dutch (3-1).
Rhea Taylor reached on an error to start the bottom of the fifth, stole second and eventually scored the tying run on Stacy May-Johnson's groundout. Arioto then led off the sixth with her second homer in as many days against Dagmar Bloeming (1-1).
Chelsea Thomas (1-0) threw two scoreless innings of relief to get the win.
Eriksen left pleased a day after calling his team out for what he felt was a lacklustre effort in the victory against Australia.
"I don't think that was our game and he knew it and we knew it," Arioto said. "We came out today and wanted to show what we're about and show ourselves what we're about. ... This was what we wanted."