Holmes, who leads the team with 11 RBIs, came to the plate in the top of the sixth hitless with a sacrifice bunt. Tara Harbert kicked off the frame with a flare single and Marston singled down the left-field line. Clarisa Navarro was hit by the pitch, setting the scene for Holmes, who sent a first-pitch offering from Shayla Sashavar over the left-field fence to give the U.S. a 9-1 lead.
"I was thinking about having an aggressive at-bat," said Holmes. "I was tired early on in the game and struck out looking earlier. I was joking with Jenny Dalton-Hill before the at-bat and told her that I may not come back in one piece because I was going to swing out of my shoes."
Marston improved to 2-0 on the mound in the World Cup after striking out two and walking one. Navarro was 3-for-3 with an RBI while Harbert drove in a run on 2-for-3 hitting. Marston currently leads the U.S. with a .733 batting average in five games and has a team-high 11 hits.
"We keep improving every game," said head coach Don Freeman. Our pitching has been phenomenal. In four games we've given up just one run. Jenna had a wonderful day. I'm really excited about the progress we're making. Everyone is contributing in good, positive ways."
Team USA got off to an early start behind Harbert who was hit by the pitch to lead off the top of the first. After Harbert's fifth stolen base of the tournament, Marston lined the next offering from starter Cindy Savaadra to right, pushing Harbert to third. Navarro drove in the first run for USA sending a single through the left side, prompting Canada to go to the bullpen and hand the ball to reliever Melissa Armstrong. Dalton-Hill tacked on another run for the U.S., bouncing a grounder to third, scoring Marston.
Team USA extended its lead to three in the top of the third on a hit by Sarah Gascon to score Navarro, who had reached safely on a walk and took second on the fielder's choice by Dalton-Hill.
Canada threatened in the bottom of the fourth, loading the bases with one out on consecutive singles and a walk. Stephanie Savoie put the Canadians on the board with a sacrifice fly to right, plating Kate Psota but Marston struck out Meagan Cornelssen to end the inning.
The U.S. loaded the bases in the top of the fifth on a pair of singles and a walk, forcing Canada to go to the bullpen for a second time and give the ball to Jessica Berube. Dalton-Hill missed the bunt on a squeeze play but Marston escaped the run-down and stole home, giving USA the 4-1 edge. Gascon was intentionally walked to load the bases again for Veronica Alvarez, who worked a 3-2 walk to push across Navarro.
Following USA's four-run sixth, Malaika Underwood tripled to lead off the top of the seventh and scored on a sacrifice fly by Harbert to extend USA's lead to 10-1. Marston followed with a double to right and took third on the fielder's choice by Holmes. Anna Kimbrell was hit by the pitch to load the bases with two outs but pitcher Martine Nadeau induced an inning-ending grounder to second.
Savaadra fell to 0-1 after giving up two runs on two hits and did not register an out. Armstrong allowed three runs in four innings.
The U.S. takes on host Venezuela on Thursday night at 7:30 p.m. EDT.