Canada and New Zealand won all three of their games on the opening day of the season-opening World Rugby Women's Sevens Series event in Denver.
Twelve teams have headed to the United States for the first round of the circuit with competition taking place over two days at Infinity Park.
Five other rounds will take place in Dubai, Australia, Japan, Canada and France, with the top four teams at the end of the series qualifying for the Tokyo 2020 Olympic Games.
Canada and Rugby World Cup Sevens 2018 champions New Zealand were unbeaten at the end of the first day.
The Canadians defeated Fiji 26-7, Ireland 24-12 and France 24-10, while New Zealand were victorious against China 45-0, England 28-7 and hosts the United States 35-12.
These results have propelled Canada and New Zealand, alongside Olympic champions Australia, Ireland, England, Russia, France and the US, into the top tier of the competition, with quarter-finals being played tomorrow.
New Zealand will meet Ireland, Canada will play Russia, England and France will face off and Australia will go up against the US.
Mexico failed to score a single point against any of their opposition, losing 53-0 to Australia, 58-0 to Mexico and 46-0 to Spain.
Fiji and China were also defeated in all three games, while Spain only recorded the win against Mexico.
These four teams have gone into the bottom tier of the tournament, with Spain meeting Mexico tomorrow followed by Fiji against China.