Goals matter in the group stage.
And statements matter in soccer's biggest tournament.
"Obviously we have the utmost respect for everyone we play, but it's the World Cup," said captain Megan Rapinoe.
RELATED: Women's national soccer team players sue for equitable pay
Alex Morgan tied the tournament record with five goals and the United States opened with a historic 13-0 rout of Thailand on Tuesday night. Samantha Mewis and Rose Lavelle each added a pair of goals for the United States, which broke the record for goals and margin of victory in a World Cup game.
Rapinoe, Lindsey Horan, Mallory Pugh and Carli Lloyd also scored. The previous record margin was Germany's 11-0 victory over Argentina in 2007.
Morgan tied Michelle Akers' record for World Cup goals, set in the quarterfinals against Taiwan in 1991. The team's seven different scorers also set a tournament record.
The @USWNT is something to smile about. It was great to celebrate with them back in 2015 and I'm excited to root them on in their drive to earn their fourth star. Best of luck to these champions for equality, on and off the field. #OneNationOneTeam pic.twitter.com/AHcHGATy5S— Barack Obama (@BarackObama) June 11, 2019
Lloyd, 36, became the oldest American woman to score at a World Cup and joined Germany's Birgit Prinz as the only players to score in five straight World Cup games.
The United States faced criticism over its relentless attack. The Americans led 3-0 at the break and then broke the match open in the second half, with the players celebrating goal after goal.
The Americans meant no disrespect, said Morgan, but they simply wanted to position themselves for a run at a second consecutive title.
"We really just came into the game really wanting to showcase ourselves," Morgan said. "Every goal matters in this tournament and that's what we were working on."
Asked about the lopsided score, U.S. coach Jill Ellis wondered if a 10-0 victory in a men's World Cup would elicit the same questions.
"This is a world championship, so every team here has been fantastic to get to this point. And I think that to be respectful to opponents is to play hard against opponents, and as Alex said, it's a tournament where goal differential is important," Ellis said.
The two teams were the last to kick off in the group stage for the monthlong tournament. Host France opened the World Cup before a sellout crowd in Paris on Friday night with a 4-0 victory over South Korea.
Ranked No. 1 in the world, the Americans had dropped only one match in their previous 38, a loss to France in Le Havre in January. The team was 7-1-2 overall this year, with six straight wins going into the World Cup.
The last time the Americans played in the sport's top tournament, Lloyd had a hat trick in the first 16 minutes and the United States beat Japan 5-2 in Canada for the trophy.
The U.S. pounced early against Thailand, too, on Morgan's header in the 13th minute off Kelley O'Hara's precisely placed cross. Mewis, Lavelle and Horan were all making their World Cup debuts.
"When you get a deluge of goals like that, it's a good feeling," Ellis said. "It builds confidence."
Thailand, ranked No. 34 in the world, was clearly outmatched even though the team has shown progress on the world stage. Making its World Cup debut in 2015 four years ago, Thailand finished third in its group but earned its first win, a 3-2 victory over Ivory Coast.
At the final whistle, Lloyd and Christen Press were seen consoling the Thailand goalkeeper. Morgan put her arm around Thailand's Miranda Nild, who was wiping away tears on the field. Nild and Morgan both played college soccer for the California Golden Bears.
"They were disappointed of course, they intended to make an impression in this first match and they were disappointed," coach Nuengrutai Srathongvian said through a translator. "Yes, they are all athletes and they will be resilient. We've got two more games to play and we need to bounce back."
Srathongvian said soccer in Thailand is still growing and there is a limited pool of players to draw from.
The World Cup comes at a time when female players across the globe are seeking better treatment, conditions and pay. The U.S. national team has long championed equal rights, and players collectively filed a lawsuit earlier this year that alleges discrimination by the U.S. Soccer Federation and are seeking pay equitable with that of the men's national team.
The players say the lawsuit is on hold while they're in France. But a pair of prominent well-wishers on Twitter referenced the team's pursuit of equality.
"The @USWNT is something to smile about. It was great to celebrate with them back in 2015 and I'm excited to root them on in their drive to earn their fourth star. Best of luck to these champions for equality, on and off the field," wrote former President Barack Obama.
Tennis legend Billie Jean King weighed in: "The pursuit of a record 4th World Cup trophy for the #USWNT officially begins today, but the journey has been years in the making. You have the support of a nation behind you. Get that win, and then get the equal pay you deserve!"
Ellis made some lineup moves for the match in the absence of defender Becky Sauerbrunn, whom the team said was held out as a precaution with a minor quad injury. Julie Ertz was moved to the backline and Mewis got the start in the midfield.
Morgan, U.S. Soccer's 2018 Player of the Year, now has 106 international goals. Playing in her third World Cup, she was named player of the match.
It came close to the team's biggest rout ever. The U.S. beat the Dominican Republic 14-0 in a 2012 Olympic qualifier in Vancouver, British Columbia.
Up next for the U.S. is World Cup newcomer Chile on Sunday in Paris. In the final group match before the knockout round, the Americans will travel to Le Havre to face nemesis Sweden, who they've been grouped with six times in World Cup play.
In the last meeting between the teams, Sweden ousted the United States in the quarterfinals at the 2016 Olympics. Afterward, former U.S. goalkeeper Hole Solo called Sweden "cowards" for bunkering on defense. Alyssa Naeher has since replaced Solo, who was dismissed from the team.
Sweden defeated Chile 2-0 earlier on Tuesday in Rennes, a match that featured a 40-minute weather delay.