All 22 starters from the North Carolina Courage and Portland Thorns, along with reserves from both teams, knelt during the national anthem before the opening game of the NWSL Challenge Cup on Saturday.
All players wore Black Lives Matter shirts over their jerseys during the anthem and Black Lives Matter armbands during the game.
The game in Herriman, Utah, marked the return of professional team sports leagues in the United States. The leagues had been on hiatus since March due to the coronavirus pandemic.
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Players from the two teams issued a joint statement shortly before kickoff.
"We took a knee today to protest racial injustice, police brutality, and systemic racism against Black people and people of color in America," the statement read. "We love our country and we have taken this opportunity to hold it to a higher standard. It is our duty to demand that the liberties and freedoms this nation was founded upon are extended to everyone."
Starters and reserves also knelt briefly for a second time immediately before kickoff. Most European professional soccer leagues adopted that gesture in recent weeks in response to the protests following the death of George Floyd, a Black man who died after Derek Chauvin, a white police officer, kneeled on his neck for nearly eight minutes in Minneapolis.
You love to see it. You love to see these women using their voice, demanding better for America, and for black people and people of color. @TheNCCourage and @ThornsFC kneeling in solidarity with @Kaepernick7 and @Blklivesmatter ✊?✊?✊?✊?✊? pic.twitter.com/8Urlj5FMPn
— Megan Rapinoe (@mPinoe) June 27, 2020
Fans will not be in attendance for any of the games during the monthlong tournament in Utah, but the anthem was played live on the field and broadcast live on CBS.
In addition to kneeling during the anthem for two games with the United States women's national team in 2016, Megan Rapinoe also knelt before an NWSL game while playing with the Seattle Reign.
Rapinoe, who now plays for OL Reign -- as that team was rebranded this offseason -- tweeted her support for the players after seeing the display.
"You love to see these women using their voice, demanding better for America, and for black people and people of color," the post said, in part.