The American team triumphed in a match against Team Europe at the RT Torax Arena in the city in the Czech Republic.
A strong performance saw the US team emerge as comfortable 7-0 winners in the tie.
The defending champions were unable to repeat the feat when they faced the challenge of neighbours Canada in their second tie.
Canada produced a strong defensive display and ultimately secured a narrow 1-0 win in their match.
The result avenged Canada’s 4-3 defeat to the US yesterday.
Canada went on to beat Team Europe 7-0 later in the day.
Teams are due to face each other twice, with the two best advancing to the final.
This year’s competition is due to conclude on Saturday (May 5).
Competition is taking place alongside the Women’s World Development Cup, which will see participants from more than 10 countries compete until Sunday (May 6).
The aim of the event is to identify and form new athletes and take the sport to new regions.
Rachel Homan’s rink was dominant from start to finish over the United States in an 11-3 victory, improving the Canadians’ record to 1-3 after the team opened their tournament with three-straight losses.
Canada jumped out to a 3-0 lead after the first end and never looked back. The Canadians scored three points in the fifth end and four in the seventh to put the nail in the coffin of the Americans, who drop to 2-3 in the tournament.
It was the Canadian women’s first game since the burned rock controversy vs. Denmark, when Homan chose to remove a rock that was slightly touched by a Danish sweeper’s broom. Denmark won that game, 9-8.
Homan and her teammates held a closed-door meeting after that loss, with a renewed focus on ignoring the first three matches and starting anew.